Ek = 1/2 mv^2
9 × 10^4 = 1/2 × 800 × v^2
9 × 10^4/400 = 400 v^2 / 400
9 × 10^4/400 = v^2
√225 = v
15 ms⁻¹ = v
That's the only way I know how to work it out
I think in this case velocity and speed would be considered the same because me
s = d/t and v=d/t
one is distance travelled and the other is displacement of a body
18 through 22 multiple choice please help
Answer:
18:equilibrium
19:10.8
20:separating the surfaces with a layer of air
21:it remains motionless
22:cm/s
( the answer only for points will be reported ) A crane lifts a load of 36000N to a height of 50 metre in 1 minute . What is the power of the crane ?
Answer:
- 30 kW
Explanation:
IDEA:
Power of an object that does work(source) is given by:
[tex] \boxed{ \mathsf{power = \frac{work \: done}{time} }}[/tex]
where work done is mostly shown as the Force applied on an object to Displace it through some distance in the same direction as the Force.
[tex] \boxed{ \mathsf{ work = force \times displacement}}[/tex]
___________________
INFORMATION:
In the question,
The source of power is the crane, while the object is a load of 36000N.
Note, what's given is the force, not the mass. Since, the SI unit of mass is kg and that of Force is Newton(N).
[The weight of the load is represented in Newton, since weight of an object is the amount of Force with which the Earth attracts that object]
I) work done
So,
Force = 36000NDisplacement = 50 m=> Work = 36000 × 50
= 1,800,000 J
(The SI unit of work is Joules(J)).
___________________
II) power
After getting the amount of work done, now we have to place it in the formula for power.
That is:
[tex] \boxed{ \mathsf{power = \frac{work \: done}{time} }}[/tex]
Note, During calculations, all quantities must be in their SI units.
SI unit for time is Seconds (s)
But the time we have is in minutes.
___________________
Converting time from minutes to Seconds:
1 minute = 60 Seconds.
Hence,
time = 60 s[tex] \implies \mathsf{power = \frac{1800000}{60} } \: [/tex]
=> power = 30,000 W
(SI unit of power is Watts(W))
To write four zeroes with a 3 and W is a lot of effort. So, we can look for simple expressions like kilowatts(kW) that can express bigger quantities in lesser terms.
1000 W = 1 kW
•°• 30,000 W = 30 kW.___________________
Direction and sign:
The crane displaces the load in an upward direction (from the term "lifts")
But, the Force is acting downwards, as the weight of the body is always towards the Earth.
Since, the directions of Force and displacement are opposite, a minus takes its place in front of both Work and power.
___________________
Therefore, the final answer will be:
Power of the crane = - 30 kWPlz help!
A person walks the path shown
below. The total trip consists of
four straight-line paths. At the end of the walk, what is the person's
resultant displacement measured from the starting point?
The analytical method for the sum of vectors allows to find the result for the sum of the vectors is:
The resulting vector has a modulus of R = 239.99 m and an angle of θ= 212.8º
The displacement is a vector quantity, therefore vector algebra must be used to perform the addition of vectors, in general there are two methods:
Graphic. In this case, the origin of a vector is placed at the tip of the previous one and the resulting vector goes from the origin of the first vector to the tip of the last, this method is not very precise. Analytical. In this method the vectors are decomposed into a coordinate system, the sum of the components is performed and the resulting vector is built, this method is very expensive.
Indicate in the graph a Cartesian coordinate system, let alone the West - East axis coincide with the x axis. Let's use trigonometry to decompose the vectors.
Vector A.
Aₓ = 100.0 m
Vector B.
B_y = -300.0 m
The negative sign indicates that it goes in the negative direction of the y-axis
Vector C.
We use trigonometry.
The angle measured from the positive side of the x-axis counterclockwise is
θ = 180 + 30 = 210
sin 210 = [tex]\frac{C_y}{C}[/tex]
cos 210 = [tex]\frac{C_x}{C}[/tex]
C_y = C sin 210
Cₓ = C cos 210
C_y = 150.0 sin 210 = -75.0 m
Cₓ = 150.0 cos 210 = -129.9 m
Vector D.
The angle from the positive side of the x-axis counterclockwise.
θ = 180-60 = 120º
sin 120 = [tex]\frac{D_y}{D}[/tex]
cos 120 = [tex]\frac{D_x}{D}[/tex]
D_y = D sin 120
Dₓ = D cos 120
D_y = 200.0 sin 120 = 173.2 m
Dₓ = 200.0 cos 120 = -100.0 m
we add the component with algebraic sum.
x = Aₓ + Cₓ + Dₓ
y = B_y + C_y + D_y
x = 100 - 129.9 -100 = -129.9 m
y = -300 - 75.0 + 173.2 = -201.8 m
We construct the resulting vector.
We use the Pythagorean theorem for the Modulus.
[tex]R+ \sqrt{x^2 +y^2}[/tex]
R = [tex]\sqrt{129.9^2 + 201.8^2 }[/tex]
R = 239.99 m
We use trigonometry for the angle.
tan θ = [tex]\frac{y}{x}[/tex]
θ = [tex]tan^{-1} \frac{y}{x}[/tex]
θ = [tex]tan^{-1} \frac{201.8}{129.9}[/tex]tan-1 (201.8 / 129.9)
θ = 57.2º
Since the two coordinates are negative, this angle is in the third quadrant; to measure it from the positive side of the x-axis.
θ = 270 - θ'
θ = 270 - 57.2
θ = 212.8º
In conclusion using the analytical method for the sum of vectors we can find the result for the sum of the vectors is:
The resulting vector has a modulus of R = 239.99 m and an angle of θ= 212.8º
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Block A has a mass of 2kg and a speed of 50 m/s along the positive x axis.
Block B has a mass of 4 kg and a speed of 25 m/s along the negative x axis.
The two blocks collide head-on in a perfectly elastic collision.
Determine the velocity of each mass after the collision.
Momentum is conserved, so
(2 kg) (50 m/s) + (4 kg) (-25 m/s) = (2 kg) v₁' + (4 kg) v₂'
where v₁' and v₂' are the velocities of the two blocks after the collision. Simplifying this gives
100 kg•m/s - 100 kg•m/s = (2 kg) v₁' + (4 kg) v₂'
0 = (2 kg) v₁' + (4 kg) v₂'
v₁' = -2v₂'
Energy is also conserved, so
1/2 (2 kg) (50 m/s)² + 1/2 (4 kg) (-25 m/s)² = 1/2 (2 kg) (v₁')² + 1/2 (4 kg) (v₂')²
Simplifying yields
2500 J + 1250 J = (1 kg) (v₁')² + (2 kg) (v₂')²
3750 J = (1 kg) (v₁')² + (2 kg) (v₂')²
Substitute v₁' = -2v₂' and solve for v₂' :
3750 J = (1 kg) (-2v₂')² + (2 kg) (v₂')²
3750 J = (6 kg) (v₂')²
(v₂')² = 625 J/kg = 625 m²/s²
v₂' = 25 m/s
Then the first block has final velocity
v₁' = -2 (25 m/s)
v₁' = -50 m/s
PLEASE HELP I WILL MARK BRAINLIST!!
The diagram shows a swinging pendulum. Which best explains what happens to the motion of the pendulum due to the law of conservation of energy?
The pendulum will slow down and eventually stop moving as the mechanical energy transforms to thermal energy.
The pendulum will slow down and eventually stop moving as the mechanical energy disappears.
The pendulum will continue moving at the same speed because mechanical energy is created as the pendulum moves.
The pendulum will slow down but will not stop moving because some of the mechanical energy is destroyed.
The pendulum bob slow down and eventually stop as it loses it energy due to friction or air resistance. All its kinetic energy has been transformed to potential energy. None of the options is correct
OSCILLATORY MOTIONThe to and fro movement of an object or particle is known as oscillatory motion. Such motion repeats itself. Examples are;
Pendulum boba diving boardthe strings of a plucked guitarthe prongs of a tuning fork struck with a hard objectthe vertical movement of a disturbed mass on a spiral spring.The given diagram shows a swinging pendulum. And the option which best explains what happens to the motion of the pendulum due to the law of conservation of energy is
The pendulum will slow down and eventually stop moving when it loses energy because of friction or air resistance as the kinetic energy transforms to potential energy
The mechanical energy involve are potential and kinetic energy. Both energies reduce as they gradually lost some of their energies due to air friction between the bob and the air. Some of the lost energies may be transformed to thermal energy.
The pendulum bob slow down and eventually stop because it loses its mechanical energy due to air resistance or friction.
Therefore, the option A which state that "The pendulum will slow down and eventually stop moving as the mechanical energy transforms to thermal energy" can be considered. But none of the option best explain what happens to the motion of the pendulum.
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What force is responsible for how magma flows and rocks stack up on top of one another?
Question 6 options:
Electroweak and Strong
Nuclear
Electromagnetic
Gravitational
Gravitational force is responsible for how magma flows and rocks stack up on top of one another.
Gravitational force is the force hat attracts all objects to the center of the earth. The force of gravity accounts for the fact that when an object is thrown up, it falls back to the earth.The force that is responsible for how magma flows and rocks stack up on top of one another is the gravitational force.Hence, it is the gravitational force that is responsible for how magma flows and rocks stack up on top of one another.
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Your mother asks you to carry a load of wood to the fireplace and lower it to the hearth. In doing this you have used your arms as levers. Which statement describes this as a class three lever?
Question 13 options:
The wood in your hands was the fulcrum, the load your elbow, and the effort (input force) was supplied by your arm muscles.
The wood was the load in your hands, the fulcrum was your elbow and the effort (input force was supplied by your arm muscles.
The fulcrum was the muscles in your arms, the load was the wood in your hands and the effort (input force) was the elbow.
Answer: The correct answer is the weight of the wood.
Explanation:
Hope this helps
which research model refers to the study of an individual group or community over a predetermined period
Developing Psychological Theories: Mastery Test
-
Hope this helps :)
-
Given that 1 pound is equal to 4.45 newton’s what is the weight of a 500N child in pounds?
Answer:
112.36 pounds
Explanation:
Since 1 pound = 4.45 Newtons, a 500N child in pounds = 500÷4.45 = 112.36 pounds (approximately).
A 100 g mass of tungsten at 100.0°C is placed in 200 g of water at 20.0°C. The
mixture reaches equilibrium at 21.6°C. Calculate the specific heat of tungsten
The specific heat capacity of tungsten given the data from the question is 0.17 J/gºC
Data obtained from the questionMass of tungsten (M) = 100 g
Temperature of tungsten (T) = 100 °C
Mass of water (Mᵥᵥ) = 200 g
Temperature warm water (Tᵥᵥ) = 20 °C
Specific heat capacity of the water (Cᵥᵥ) = 4.184 J/gºC
Equilibrium temperature (Tₑ) = 21.6 °C
Specific heat capacity of tungsten (C) = ?
How to determine the specific heat capacity of tungstenHeat loss = Heat gain
MC(T – Tₑ) = MᵥᵥCᵥᵥ(Tₑ – Tᵥᵥ)
100 × C × (100 – 21.6) = 200 × 4.184(21.6 – 20)
100 × C × 78.4 = 1338.88
Divide both sides by 100 × 78.4
C = 1338.88 / (100 × 78.4 )
C = 0.17 J/gºC
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Which would ba another example of newtons first law?
How do you un rewrap something?
Forces are needed to make a car do which of these?
slow down
speed up
stay on the ground
all of the above
[URGENT] A swimmer wants to end up at a dock due north of her starting position on the south shore of a river. In still water her maximum speed is 1.25m/s. The river has a current flowing 0.35m/s [E].
a.) calculate the direction that she must aim herself through the water to arrive at the dock.
b.) how long will it take for the swimmer to cross the river, if the distance from the starting point to the dock is 300 m?
Please show all your work, thanks
Explanation:
As you can see in the picture, we want the swimmer to go on a straight line, so the speed of the water must be equal to the speed of the swimmer along the x-axis. We also know the value of v, so we can calculate the of the cosine of the angle (alpha) between Vx and V. Thanks to the fundamental relation of gioniometry (cos^2(x) + sin^2(x) = 1) we can find the sine of alpha and calculate Vy. With Vy we can calculate the time that the swimmer will use for reaching the dock: s = Vy * t => t = s/(Vy).
I'll let you do all the calculations, you just have to plug in values.
a)The direction that she must aim herself through the water to arrive at the dock will be 73.7°.
b)The time it takes for the swimmer to cross the river will be 240 seconds.
What is speed?Speed is defined as the rate of change of the distance or the height attained. it is a time-based quantity. it is denoted by u for the initial speed while v for the final speed. its si unit is m/sec.
Given data;
The maximum speed of the swimmer In still water,v=1.25m/s.
Speed of river = 0.35m/s [E]
α is the direction that she must aim herself through the water to arrive at the dock.
t is the time it takes for the swimmer to cross the river
The distance from the starting point to the dock is,s = 300 m
If the swimmer were to swim straight, the water's speed along the x-axis would have to match that of the swimmer.
[tex]\rm v_w = v_x = 0.35 \ m/sec[/tex]
α is the angle between vx and v
The value of the
[tex]\rm cos \alpha = \frac{v_x}{v} \\\\ \alpha = cos ^{-1}(\frac{0.35}{1.25} )\\\\ \alpha = 73.7 ^0[/tex]
The time that the swimmer will use for reaching the dock;
s = V×t
t = s/(v)
t=300 m / 1.25 m/sec
t = 240 seconds
Hence, the direction that she must aim herself through the water to arrive at the dock. and it takes for the swimmer to cross the river will be 73.7° and 240 seconds respectively.
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Classify the statement below as either Speed or Velocity?
A jeep was driving 40 mph
heading to the grocery store.
Answer:
Hello There!
It is Speed.
[tex]\Large\bold\red{Reason}[/tex]
Because in the question it is said that at which speed car is travelling.
Speed is a scalar quantity.
If it is velocity then first know this that it is a vector quantity.
It must include both magnitude and direction.
If it is velocity then it would be 40 mph east or west or north or south.
I hope it is helpful to you...Cheers!_____________a convex lens has a focal length of 0.5 it is combined with a second lens so combination has power 2.5 diopter which of the following could be second lens
A) concave lens focal length 2m
B) convex lens focal length 0.5m
C) concave lens 0.5m
D) convex lens 2m
Answer:
concave lens focal length 2m
Which statement accurately describes how the acceleration of an object in free fall changes?
O A. It accelerates downward at a constant rate.
O
B. It accelerates downward at an increasing rate.
C. It accelerates downward at an irregular rate.
D. It accelerates downward at a decreasing rate.
Answer: A
Explanation: An object in free fall only is affected by gravity, so the acceleration is 9.8 m/s²
When dribbling a ball, the ______________ should control the direction and downward motion of the ball.
Answer:
gravity
Explanation:
keeps the ball down on the surface
When dribbling a ball, the gravity should control the direction and downward motion of the ball.
What is projectile motion?When a particle is hurled obliquely near the surface of the earth, it travels along a curved path while accelerating continuously in the direction of the planet's centre (we assume the particle stays close to the surface of the globe). Such a particle's motion is known as projectile motion, and its route is referred to as a projectile.
Two distinct rectilinear motions occur simultaneously in a projectile motion:
Uniform velocity along the x-axis is what causes the particle to move horizontally (ahead).Uniform acceleration along the y-axis is what causes the particle to move vertically (downwards).When a ball is sent into the air at a certain speed, the only force acting on it is the acceleration caused by gravity (g).
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The definition of energy is the ability to ___________.
(Hint: one word)
Connor rode an inner tube down a river. For 4.6 minutes, he moved downriver at 15 meters per minute. During this time, how far did he move?
answers:
3.26 meters
3.26 minutes
69 meters
69 minutes
Answer:
69 meters
Explanation:
Two forces that act on very small distances (smaller than you can see ) are
a bullet is fired out of a gun up at an angle with the horizontal. if its initial horizontal velocity is 10m/s what is the most likely horizontal velocity after two seconds
Hi there!
[tex]\large\boxed{10 m/s}}[/tex]
When a projectile is launched, the HORIZONTAL component remains constant.
The force of gravity only changes the vertical component of the velocity.
As the two components are completely independent of one another, the horizontal component is UNCHANGED.
why we use light-years in space verses other units of distance?
Answer:
The light year is used to measure distances in space because the distances are so big that a large unit of distance is required.
you push on a 24.5kg bag of sand and give it an acceleration of 2.30 m/s ^s. what is the magnitude of the force the bag returns …
Answer:
Below in bold.
Explanation:
Newton's Second Law:
Force = mass * acceleration
So
Force = 24.5 * 2.3
= 56.35 Newtons.
The Sun has a mass of 1.99 x 10^30kg [^30 is an exponent] and is 1.5 x 10^11m [^11 is an exponent] from the earth. The planet Earth is 5.98 x 10^24kg [^24 is an exponent]. What is the gravitational attraction between the sun and the earth? G=6.67×10^-11 (-11 is an exponent)
We are given –
Mass of earth,m = 5.98×10²⁴ kgMass of sun, M= 1.99×10³⁰ kgDistance between Earth andSun, r= 1.5×10¹¹ m
G = 6.67×10⁻¹¹ Nm²/kg²We are asked to find the gravitational attraction between the sun and the earth.
By Universal Law of Gravitation, we know that –[tex]\qquad[/tex] [tex]\pink{\twoheadrightarrow\sf F = \dfrac{GMm}{r²}}[/tex]
Substituting values, we get –
[tex]\qquad[/tex] [tex]\twoheadrightarrow\bf F = \dfrac{6.67×10^{-11}\times 5.98×10^{24}\times 1.99×10^{30}}{(1.5×10^{11})^2}[/tex]
[tex]\qquad[/tex] [tex]\twoheadrightarrow\bf F = \dfrac{6.67×10^{-11}×5.98×10^{24}×1.99×10^{30}}{2.25×10^{22}}[/tex]
[tex]\qquad[/tex] [tex]\twoheadrightarrow\bf F = 35.27×10^{21}[/tex]
[tex]\qquad[/tex] [tex]\pink{\twoheadrightarrow\bf F = 3.53×10^{22} N}[/tex]
Henceforth ,gravitational attraction between the sun and the earth. is 3.53×10²²N .______________________________________________
How many cm3 are there in 1 dm3?
The answer is in the picture.
A roller coaster
produces acceleration due
to changes in both speed
and direction. Applying
Concepts Describe the
acceleration occuring at this
instant on the
rollercoaster ride.
Answer:
the answer is the rollar coster
Explanation:
because the rollar coster is
the breaks on a 15,680 N car exert a stopping force of 640 N.
A 0.15 kg baseball moving at 20 m/s is stopped by a player in 0.010 s. What is the average force of the ball?
Answer: 300N
Explanation:
Impulse= Mass * Velocity
F.T = M * V
F= MV/T
F= (0.15*20)/ 0.01
F= 300N
the purpose of many scientific investigations is to test a {n}
Answer:
Scientific investigation is a quest to find the answer to a question using the scientific method.
Explanation:
the scientific method is a systematic process that involves using measurable observations to formulate, test or modify a hypothesis.