A stone is thrown vertically upwards. It takes 2 seconds to reach it highest point the acceleration due to gravity is 10m/s. With what velocity must it be thrown ?
Answer:
The velocity the stone must be thrown with is 20 m/s.
Explanation:
Given;
time taken for the stone to reach it highest point, t = 2 s
acceleration due to gravity, g = 10 m/s²
The maximum height reached by the stone at the given time is calculated as;
[tex]h = \frac{1}{2}gt^2\\\\h = \frac{1}{2}*10*2^2\\\\h = 20 \ m[/tex]
Determine the initial of the stone;
v² = u² + 2gh
where;
v is the final velocity of the stone at maximum height = 0
u is the initial velocity of the stone = ?
0 = u² - 2(10 x 20)
0 = u² - 400
u² = 400
u = √400
u = 20 m/s
Therefore, the velocity the stone must be thrown with is 20 m/s.
For a substance to change phases, the amount of Internal energy must change. Water exists in three phases: liquid, solid (ce), and gas (water vapor). Which of the following lists the
phases in order of increasing total energy?
O
gas, liquid, solid
solid, gas, liquid
solid, liquid, gas
oliquid, gas, solld
A vector is expressed in polar notation as A⃗ = ( 35.0 N, 37 ∘) Calculate the components of the vector, and enter them (separated by a comma) in the answer box to express the vector in rectangular notation.
Answer:
A = (27.95 N, 21 N)
Explanation:
The polar co-ordinates are given as:
(r,θ) = (35 N, 37°)
Now, to convert this into polar co-ordinates (x, y), we will use following relations:
r² = x² + y²
(35)² = x² + y²
1225 = x² + y² ----------- equation (1)
and
tan θ = y/x
tan 37° = y/x
y = 0.753 x ------------------- equation (2)
Substituting this value in equation (1):
1225 = x² + (0.753 x)²
1225 = 1.567 x²
x² = 1225/1.567
x = √781.32
x = 27.95 N
using this value in equation (2)
y = (0.753)(27.95 N)
y = 21 N
Therefore, the vector can be represented in polar co-ordinates as:
A = (27.95 N, 21 N)
How is energy stored in food? Is the form of energy stored in food different from the form stored in gasoline? Explain.
Answer:
There are little tiny batteries that are contained within the molecules of the food. The sun charges these batteries, and when the food is eaten, the energy from the batteries flows through the acids in the stomach, which gives the person or animal energy. In gasoline, the energy is created when the gasoline is set on fire and burned, there is no energy within it already. So they are different forms of energy. Hope this helps!
A student determines the density ρ of steel by taking measurements from a steel wire
Mass- 6.2 +-0.1g
Length- 25.0 +-0.1m
Diameter- 2.00 +-0.01mm
He uses the equation ρ= 4m/πd^2l
What is the percentage uncertainty in his calculated value of density ?
Answer:
The percentage uncertainty in his calculated value of density is [tex]\pm 0.713\,\%[/tex].
Explanation:
We can estimate the absolute uncertainty by the definition of total differential. That is:
[tex]\Delta \rho \approx \frac{\partial \rho}{\partial m}\cdot \Delta m + \frac{\partial \rho}{\partial d}\cdot \Delta d + \frac{\partial \rho}{\partial l}\cdot \Delta l[/tex] (1)
Where:
[tex]\frac{\partial \rho}{\partial m}[/tex] - Partial derivative of the density with respect to mass, measured in [tex]\frac{1}{mm^{3}}[/tex].
[tex]\frac{\partial \rho}{\partial d}[/tex] - Partial derivative of the density with respect to diameter, measured in grams per cubic milimeter.
[tex]\frac{\partial \rho}{\partial l}[/tex] - Partial derivative of the density with respect to length, measured in grams per cubic milimeter.
[tex]\Delta m[/tex] - Mass uncertainty, measured in grams.
[tex]\Delta d[/tex] - Diameter uncertainty, measured in milimeters.
[tex]\Delta l[/tex] - Length uncertainty, measured in milimeters.
[tex]\Delta \rho[/tex] - Density uncertainty, measured in grams per cubic milimeters.
Partial derivatives are, respectively:
[tex]\frac{\partial \rho}{\partial m} = \frac{4}{\pi\cdot d^{2}\cdot l}[/tex] (2)
[tex]\frac{\partial \rho}{\partial d} = -\frac{8\cdot m}{\pi\cdot d^{3}\cdot l}[/tex] (3)
[tex]\frac{\partial \rho}{\partial l} = - \frac{4\cdot m}{\pi\cdot d^{2}\cdot l^{2}}[/tex] (4)
And we expand (1) as follows:
[tex]\Delta \rho \approx \frac{4\cdot \Delta m}{\pi\cdot d^{2}\cdot l} - \frac{8\cdot m\cdot \Delta d}{\pi\cdot d^{3}\cdot l}-\frac{4\cdot m\cdot \Delta l}{\pi\cdot d^{2}\cdot l^{2}}[/tex]
[tex]\Delta \rho \approx \left(\frac{4}{\pi\cdot d^{2}\cdot l}\right)\cdot \left(\Delta m -\frac{m\cdot \Delta d}{d}-\frac{m \cdot \Delta l}{l} \right)[/tex] (5)
If we know that [tex]d = 2\,mm[/tex], [tex]l = 25\,mm[/tex], [tex]m = 6.2\,g[/tex], [tex]\Delta m = \pm 0.1\,g[/tex], [tex]\Delta d = \pm 0.01\,mm[/tex] and [tex]\Delta l = \pm 0.1\,mm[/tex], then the absolute uncertainty is:
[tex]\Delta \rho \approx \pm\left[\frac{4}{\pi\cdot (2\,mm)^{2}\cdot (25\,mm)} \right]\cdot \left[(0.1\,g)-\frac{(6.2\,g)\cdot (0.01\,mm)}{2\,mm} -\frac{(6.2\,g)\cdot (0.1\,mm)}{25\,mm} \right][/tex]
[tex]\Delta \rho \approx \pm 5.628\times 10^{-4}\,\frac{g}{mm^{3}}[/tex]
And the expected density is:
[tex]\rho = \frac{4\cdot m}{\pi\cdot d^{2}\cdot l}[/tex] (6)
[tex]\rho = \frac{4\cdot (6.2\,g)}{\pi\cdot (2\,mm)^{2}\cdot (25\,mm)}[/tex]
[tex]\rho \approx 78.941\times 10^{-3}\,\frac{g}{mm^{3}}[/tex]
The percentage uncertainty in his calculated value of density is:
[tex]\%e = \frac{\Delta \rho}{\rho}\times 100\,\%[/tex] (7)
If we know that [tex]\Delta \rho \approx \pm 5.628\times 10^{-4}\,\frac{g}{mm^{3}}[/tex] and [tex]\rho \approx 78.941\times 10^{-3}\,\frac{g}{mm^{3}}[/tex], then the percentage uncertainty is:
[tex]\%e = \frac{\pm 5.628\times 10^{-4}\,\frac{g}{mm^{3}} }{78.941\times 10^{-3}\,\frac{g}{mm^{3}} }\times 100\,\%[/tex]
[tex]\%e = \pm 0.713\,\%[/tex]
The percentage uncertainty in his calculated value of density is [tex]\pm 0.713\,\%[/tex].
At a local swimming pool, the diving board is elevated h = 9.5 m above the pool's surface and overhangs the pool edge by L = 2 m. A diver runs horizontally along the diving board with a speed of v0 = 2.7 m/s and then falls into the pool. Neglect air resistance. Use a coordinate system with the horizontal x-axis pointing in the direction of the diver’s initial motion, and the vertical y-axis pointing up. Let the y-axis be directed vertically down. Express the time t_w it takes the diver to move off the end of the diving board to the pool surface in terms of v_0, h, L, and g. Calculate the time, t_w in seconds, it takes the diver to move off the end of the diving board to the pool surface. Determine the horizontal distance, d_w in meters, from the edge of the pool to where the diver enters the water.
Answer:
1) The time it takes the diver to move off the end of the diving board to the pool surface, [tex]t_w[/tex], is approximately 1.392 seconds
2) The horizontal distance from the edge of the pool to where the diver enters the water, [tex]d_w[/tex], is approximately 5.76 meters
Explanation:
1) The given parameters are;
The height of the diving board above the pool's surface, h = 9.5 m
The length by which the diving board over hangs the pool L = 2 m
The speed with which the diver runs horizontally along the diving board, v₀ = 2.7 m/s
Taking [tex]t_w[/tex] = The time it takes the diver to move off the end of the diving board to the pool surface
Therefore, we have from the equation of free fall;
h = 1/2 × g × [tex]t_w[/tex]²
Where;
g = The acceleration due to gravity = 9.81 m/s²
Substituting the values, gives;
9.5 = 1/2 × 9.81 × [tex]t_w[/tex]²
[tex]t_w[/tex] = √(9.5/(1/2 × 9.81)) ≈ 1.392 s
The time it takes the diver to move off the end of the diving board to the pool surface = [tex]t_w[/tex] ≈ 1.392 s
2) The horizontal distance, [tex]d_w[/tex], in meters from the edge of the pool to where the diver enters the water is given as follows;
[tex]d_w[/tex] = L + v₀ × [tex]t_w[/tex] = 2 + 2.7× 1.392 ≈ 5.76 m
∴ The horizontal distance from the edge of the pool to where the diver enters the water ≈ 5.76 meters.
The U-tube contains a coloured liquid of density 9.6 x102 kg/m3. If the difference in height between the liquid levels in the two arms of the U-tube is 0.16m, calculate the excess pressure (above air pressure) in the cylinder. (Take g = 10 N/kg)
Explanation:
P = ρgh
P = (9.6×10² kg/m³) (10 N/kg) (0.16 m)
P = 1536 Pa
Rounded to two significant figures, the pressure is 1500 Pa, or 1.5 kPa.
The planes LA534 and LA639 are coming in for a landing on the same runway which means they are each lowering their altitude. Note that LA534 is traveling at twice the speed of LA 639. What must they do to keep from crashing into each other on the runway
Answer:
plane LA534 will have to decrease it speed by twice that of plane LA639.
Explanation:
Since both planes want to land there must be a decrease in speed.
We are told that plane LA534 velocity is twice that of plane LA639.
Now for the two planes to land without a crash. the opposite or reverse will be the case in terms of deceleration, that is
Plane LA639 will have to decrease its speed by twice the decrease in speed of plane LA534
The
of an object shows how fast the object is moving at a specific
Answer:
Speed is a description of how fast an object moves; velocity is how fast and in what direction it moves. In physics, velocity is speed in a given direction. When we say a car travels at 60 km/h, we are specifying its speed.
Lucia kicks a ball on a level playing field with an initial velocity of 11.3 m/s at an angle of 35° above the horizontal. Find: Time of flight? Horizontal distance traveled? Maximum height?
Explanation:
Given that,
Initial velocity, u = 11.3 m/s
Angle above the horizontal, [tex]\theta=35^{\circ}[/tex]
Time of flight :
[tex]t=\dfrac{2u\sin\theta}{g}\\\\t=\dfrac{2\times 11.3\times \sin(35)}{9.8}\\\\t=1.32\ s[/tex]
Horizontal distance traveled is given by :
x = ut
x = 11.3 m/s × 1.32 s
x = 14.916 m
Maximum height is given by :
[tex]H=\dfrac{u^2\sin^2\theta}{2g}\\\\H=\dfrac{(11.3)^2\times \sin^2(35)}{2\times 9.8}\\\\H=2.14\ m[/tex]
Hence, time of flight is 1.32 s, horizontal distance is 14.916 m and maximum height is 2.14 m.
Which car is accelerating?
A) a car that is unmoving
B) a car that rounds a curve at a constant speed
C) a car travels in a straight line at a constant speed
D) a car is set to a constant speed of 60 miles per hour
Answer:
The car that is accelerating is B a car that rounds a curve at a constant speed
Explanation:
Although all of the cars are at a constant speed or not moving acceleration is the change in speed or the change of directions therefore making the only car changing directions your answer.
Answer:
its B (:
Explanation:
i took the test :)
Which example illustrates Newton's second law?
A. A wheelbarrow remains stationary when no one pushes on it.
B. More mass is added to a wheelbarrow, and a larger force is
required to move it.
C. A person pushes a wheelbarrow, causing it to move forward.
D. The force of a wheelbarrow on the ground is equal to the force of
the ground on the wheelbarrow.
Answer:B
Explanation:
Mass
More mass is added to a wheelbarrow, and a larger force is required to move it - illustrates Newton's second law.
What is force?An object's push or pull is seen as exerting a force. The interaction of the objects produces push and pull. You can also use words like stretch and squeeze to describe force.
The definition of force in physics is: The push or pull on a mass-containing item changes its velocity.
Newton’s second law of motion states that “Force is equal to the rate of change of momentum. For a constant mass, force equals mass times acceleration."
Hence more mass is added to a wheelbarrow, and a larger force is required to accelerate, i.e., move it.
To find more about force, refer the link:
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Part 2: Identify the independent, dependent, and constant variables
Experiment 1: A soap manufacturer runs an experiment to compare the foaming action of different dish detergents. Equal
amounts of each brand of detergent are placed in identical containers half-filled with water. The water and dish detergent are at
a temperature of 20°Celsius. Each container is agitated for 30 seconds, and then the height of the foam is measured.
a. independent variable:
b. dependent variable:
C. constant variable(s):
What is electronegativity
A. An atoms ability to attract other electrons and form a chemical bond
Explanation:
Electronegativity is a measure of an atom's ability to attract shared electrons to itself. On the periodic table, electronegativity generally increases as you move from left to right across a period and decreases as you move down a group.
Answer:
A)
Explanation:
I took the test and got it right. Flvs
You throw an orange out a window at a height of 12.00 meters
upwards at an angle of 32° to the horizontal at a velocity of 3.5
m/s. What is the maximum height that the orange will reach?
Answer:
12.18
Explanation:
The maximum height that the orange will reach is 12.18 m.
What is projectile?When an object is thrown at an angle from the horizontal direction, the object is said to be in projectile motion.
You throw an orange out a window at a height of 12.00 meters upwards at an angle of 32° to the horizontal at a velocity of 3.5 m/s.
If u is the initial speed, the maximum height of the ball from the point of throwing is
H = u² sin²θ / 2g
Put the values, we get
H = 3.5² sin²32° / (2x9.81)
H = 0.1753 m
So, the maximum height calculated from the ground is
12 + 0.18 = 12.18 m
Thus ,the maximum height that the orange will reach is 12.18 m.
Learn more about projectile.
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!!please help !!!!! I’ll give brainliest
Answer:
45 degrees
Explanation:
a projectile travels the farthest when it is launches at the angle of 45 degree.
Convert 318 meters per second to kilometers per hour
Answer:
1144.8
Explanation:
1 meter per second is equal to 3.6 kilometers per hour
What happens to the minerals as gneiss forms from schist?
Answer:
Explanation:
Gneiss is a high grade metamorphic rock, meaning that it has been subjected to higher temperatures and pressures than schist. However, unlike slate and schist, gneiss does not preferentially break along planes of foliation because less than 50% of the minerals formed during the metamorphism are aligned in thin layers.
A 7.40-kg object initially has 347 J of gravitational potential energy. Then an elevator lifts the object a distance of 20.6 m above its previous position. How much work did the elevator perform on the object?
Answer:
W = 1493.9 J = 1.49 KJ
Explanation:
The work done by the elevator on the object will be equal to the gain in is potential energy:
W = ΔP.E
W = mgΔh
where,
W = Work = ?
m = mass of object = 7.4 kg
g = 9.8 m/s²
Δh = gain in height = 20.6 m
Therefore,
W = (7.4 kg)(9.8 m/s²)(20.6 m)
W = 1493.9 J = 1.49 KJ
An archer stands on the ground and fires an arrow at a target. A second archer stands at the top of a building and holds an arrow in his hand. Which arrow has more potential energy?
In the same scenario described in question 7, which arrow has more kinetic energy? Explain.
Answer:
The arrow of the second archer standing on a high building will have more potential energy.
The arrow of the first archer standing on ground will have more kinetic energy.
Explanation:
POTENTIAL ENERGY:
The potential energy of an object depends upon its height, as given in the formula:
P.E = mgh
Hence, the arrow with the greater height will have more potential energy.
Therefore, the arrow of the second archer standing on a high building will have more potential energy.
KINETIC ENERGY:
The kinetic energy of an object depends upon its speed, as given in the formula:
K.E = (1/2)mv²
Hence, the arrow with the greater speed will have more kinetic energy energy. Since, the second arrow is stationary, it will have zero kinetic energy. But, the first arrow will have some K.E due to its speed.
Therefore, the arrow of the first archer standing on ground will have more kinetic energy.
(a) The second archer standing at the top of the building will have more potential energy.
(b) The first archer on the ground level will have the more kinetic energy.
The potential energy of an object is the energy possessed by the object by virtue its position above above the ground.
P.E = mgh
where;
h is the height above the groundThus, the second archer standing at the top of the building will have more potential energy.
(b) The kinetic energy of an object is the energy possessed by the object due to its motion.
K.E = ¹/₂mv²
where;
v is the speed of the objectAn object in motion, has zero velocity at maximum height but maximum velocity on the ground level.
Thus, the first archer on the ground level will have the more kinetic energy.
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A box sitting still on the ground by itself has a Normal Force of 700N, what is the mass? (gravity’s acceleration is 9.80 m/s²)
Answer:
Mass, m = 71.42 kg
Explanation:
Given that,
Normal force acting on a box, F = 700 N
We need to find the mass of a box. Let it is m. Normal force acting on an object is balanced by its weight such that,
F = mg
Where m is the mass of the box
[tex]m=\dfrac{F}{g}\\\\m=\dfrac{700\ N}{9.8\ m/s^2}\\\\m=71.42\ kg[/tex]
So, the mass of the box is 71.42 kg.
in a free body diagram the weight is
Answer:
Explanation:
a. WEIGHT: As we have seen, weight is the gravitational force exerted on an object by the Earth (or any other celestial body). If an object is near the Earth's surface and has mass, then the object has a weight. The magnitude of its weight is w = mg and its direction is toward the center of the Earth.
Find the range of a projectile launched at an angle of 30° with an initial velocity of 20m/s.
Answer:
The range is 35.35 m
Explanation:
Projectile Motion
It's the type of motion that experiences an object projected near the Earth's surface and moves along a curved path exclusively under the action of gravity.
Being vo the initial speed of the object, θ the initial launch angle, and [tex]g=9.8m/s^2[/tex] the acceleration of gravity, then the maximum horizontal distance traveled by the object (also called Range) is:
[tex]\displaystyle d={\frac {v_o^{2}\sin(2\theta )}{g}}[/tex]
The projectile was launched at an angle of θ=30° with an initial speed vo=20 m/s. Calculating the range:
[tex]\displaystyle d={\frac {20^{2}\sin(2\cdot 30^\circ )}{9.8}}[/tex]
[tex]\displaystyle d={\frac {400\sin(60^\circ )}{9.8}}[/tex]
[tex]d=35.35\ m[/tex]
The range is 35.35 m
Help on this pls. !!!!!
Answer:
C
Explanation:
describe where the information and communication technology can be used it different section?
guys help me i will make you brainliest <3
Answer:
See below
Explanation:
ICT " Information and the communication technology" can be used in sectors like Telecommunications. ADB support for telecommunications and ICT is changing lives across the region. ...
ICT in Education. ICT can improve the efficiency and quality of education at all levels. ...
ICT in Public Sector Management. ...
ICT in Health. ...
ICT in Agriculture and Food Security.
( hope it helped <3 )
A car of mass 1167 kg accelerates on a flat highway from 10 m/s to 28.0 m/s. How much work does the car's engine do on the car?
Answer:
Workdone = 465766038 Joules.
Explanation:
Given the following data;
Mass = 1167
Initial velocity = 10m/s
Final velocity =28m/s
To find the workdone;
We know that from the workdone theorem, the workdone by an object or a body is directly proportional to the kinetic energy possessed by the object due to its motion.
Mathematically, it is given by the equation;
W = Kf - Ki
W = ½MVf² - ½MVi²
Substituting into the equation
W = ½(1167)*28² - ½(1167)*10²
W = ½ * 1361889* 784 - ½ * 1361889 * 100
W = 533860488 - 68094450
Workdone = 465766038 Joules.
El cloro (Z igual a 17) es un elemento utilizado generalmente en la desinfección de piscinas en la naturaleza hay 2 isótopos del cloro: el Cl-35, con una abundancia del 75% y el Cl-37 con una abudancia del 25%. Determina : a)los protones y los neutrones que hay en el nucleo de cada uno de estos isotopos b) la masa atomica media del cloro expresada en u c) el numero de atomos de cloro que hay en 15g de cloro
Answer:
a) El número de neutrones de Cl-35 es 18 y del Cl-37 es 20.
b) La masa atómica media del cloro es 35.5 uma.
c) En 15 g de cloro hay 2.55x10²³ átomos.
Explanation:
a) Para calcular los protones y neutrones de los isótopos Cl-35 y Cl-37 debemos usar la siguiente fórmula:
[tex] A = Z + N [/tex]
En donde:
Z: es el número de protones = 17
N: es el número de neutrones
A: es la masa atómica
Los isótopos de un elemento dado tienen el mismo número de protones (número atómico) y en ellos sólo varia la la masa atómica (y por ende el número de neutrones); por lo que el Cl-35 y Cl-37 tienen igual Z (17).
Para el Cl-35 tenemos:
[tex] N = A - Z = 35 - 17 = 18 [/tex]
Y para el Cl-37 tenemos:
[tex]N = 37 - 17 = 20[/tex]
Por lo tanto, el número de neutrones de Cl-35 es 18 y del Cl-37 es 20.
b) La masa atómica media del cloro está dada por:
[tex]M_{Cl} = A_{Cl-35}*\%_{Cl-35} + A_{Cl-37}*\%_{Cl-37} = 35 u*\frac{75}{100} + 37 u*\frac{25}{100} = 35.5 u[/tex]
Entonces, la masa atómica media del cloro es 35.5 uma.
c) Para encontrar el número de átomos de Cl que hay en 15 g debemos usar el número de Avogadro (6.022x10²³ átomos/mol):
[tex] N = \frac{1 mol}{35.5 g}*15 g*\frac{6.022 \cdot 10^{23} atomos}{1 mol} = 2.55 \cdot 10^{23} atomos [/tex]
Finalmente, en 15 g de cloro hay 2.55x10²³ átomos.
Espero que te sea de utilidad!
A positive ion is called a ____________ and a negative ion is called an
Answer:
Cation
Explanation:
Best way to remember this one is a CATion is PAWS-itive!
Which option is the smallest particle that represents the compound carbon
dioxide?
A. A carbon dioxide molecule B. A carbon dioxide atom
C. A carbon atom and an oxygen atom
D. A carbon ion and an oxygen ion
HELPPPPP
PLEASE I NEED THIS ANSWER FASTTTT
Answer:The answer is A
Explanation: You can instantly eliminate b and d because an ion isn't mentioned, and it is impossible to have a carbon dioxide atom. C is incorrect because there has to be two oxygen's to create a carbon dioxide molecule.
Answer:
D. A carbon dioxide molecule
Explanation:
The force that causes an object to follow a
circular path is
tion:
at o
1. an inertiali force.
2. a centripetal force.
3. a gravitational force.
CI
nents
stant
4. a fluid force.
Answer:
2.a centripetal force.