Answer:
b
Explanation:
b
Answer:
Ice melting
Explanation:
You can see ice melting and its a physical change. Iron rusting is not a physical change and wood burning is not either and garbage is not either.
A sound wave passes from air into water and then into steel. With each change in medium, the velocity of this wave will a(increase,then decrease b(decrease c(increase d( decrease,then increase ?
Answer:
a
Explanation:
because it can increase anything
In raising an object vertically at a constant speed of 2 m / s 10 watts of power is developed the weight of the object is
Answer:
5NExplanation:
Power = Workdone/Time
Since workdone = Force * distance = mgh
Power = mgh/t
Given
Power = 10watts
speed = 2m/s
Power = Weight * velocity
Substitute
10 = Weight * 2
Weight = 10/2
Weight = 5N
Hence the weight of the object is 5N
How does the number of batteries affect the strength of an electromagnet?
Answer:
The answer is below
Explanation:
It has been observed that the strength of electromagnets is based on the electrical current passing through their wires.
However, the number of batteries can affect the strength of electromagnets if only the electromagnet's resistance is what's hindering the current.
This can be observed when multiple batteries are connected thereby increasing the degrees of voltage across the electromagnet.
Which one of the following is not a member of the solar family: (a) Morning Star (b) Evening Star (c) Pole Star (d) Tailed Star plzzz answer this...
Answer:
Tailed star
Explanation:
Tailed star
How high can a 40 N force move a load, when 395 J of work is done? (Show work)
A 40 N force would move a load 9.875 m high when 395 J of work is done on the load.
What is work done?The total amount of energy transferred when a force is applied to move an object through some distance
The work done is the multiplication of applied force with displacement.
The SI unit of work done by an object is Joules.
IJ is the work done when a force of 1 N displaces an object by 1 m .
Work Done = Force * Displacement
For the given problem Force =40N and work done = 395 J
By using the above formula
Work Done = Force * Displacement
395 j = 40 N × height
height =9.875 m
Thus a 40 N force supported by a work done of 395 J moves the load up to 9.875 m height
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A block and tackle consisting of 5 pulleys is used to raised a load of 400N through a height of 10m.If the work done against friction is 100j.
Calculate;
1)The work done by the effort
2)The efficiency of the system
3)The effort applied
Answer:
1) 4000Joules
2) 25%
3) 320N
Explanation:
A block and tackle consisting of 5 pulleys is used to raised a load of 400N through a height of 10m.If the work done against friction is 100j.
Calculate;
1)The work done by the effort
2)The efficiency of the system
3)The effort applied
1) Workdone by the effort is the work input = Load * distance moved by the Load
Workdone by the effort = 400 * 10
Workdone by the effort = 4000Joules
2) Efficiency = Work output/Work input * 100
Work output = work done against friction = 100 Joules
Efficiency = 100/4000 * 100
Efficiency = 10000/4000
Efficiency = 25%
Hence the Efficiency of the system is 25%
3) Using the efficiency formula:
efficiency = MA/VR * 100
Velocity ratio = 5
MA = Load/Effort
efficiency = (L/E)/5 * 100
25 = 400/E/5 * 100
25/100 = 400/5E
0.25 = 400/5E
0.25 * 5E = 400
1.25E = 400
E = 400/1.25
E = 320N
hence the effort applies is 320N
A ball is thrown horizontally at a speed of 24 meters per second from the top of a cliff. If the ball hits the ground 4.0 seconds later, approximately how high is the cliff? I NEED HELP FOR THIS QUIZ LOL
Answer:
78.4m
Explanation:
In these situations, vertical and horizontal components need to be considered separately;
So, horizontal speed is irrelevant since we are talking about vertical height, i.e. the height of the cliff;
But, the fact that the speed is horizontal is relevant because this means the vertical speed initially is 0m/s;
The downwards movement of the ball is due to gravity, which is 9.8m/s²;
The time is given as 4.0s from the top of the cliff to the bottom;
We know the acceleration, time and initial speed so we can use this kinematic equation to solve for distance:
s = ut + ¹/₂at²
s = displacement (/distance)
u = initial vertical velocity = 0
t = time (time taken for the ball to fall) = 4
a = acceleration (downwards) = 9.8
Substitute these values into the equation to get the distance:
s = 0(4) + ¹/₂(9.8)(4)²
s = 78.4m
A washing machine is being dragged with a starting force of 380.8 N to the West, but this is reduced by friction. If the mass of the washing machine is 37 kg
and the coefficient of friction is 0.54, what was the Net acceleration experienced by the washing machine?
A 10.27 m/s^2 South
B 5 m/s^2 South
C 19.01 m/s^2 South
D 7.6 m/s^2 South
Answer:
B. [tex]5\,\frac{m}{s^{2}}[/tex] South
Explanation:
The correct statement is:
A washing machine is being dragged with a starting force of 380.8 N to the South, but this is reduced by friction. If the mass of the washing machine is 37 kg and the coefficient of friction is 0.54, what was the Net acceleration experienced by the washing machine?
The net force of the washing machine moving on the horizontal ground is equal to the external force minus the friction force, where the normal force from the ground on the washing machine is equal to its weight. The free body diagram of the washing machine is presented below. The equation of equilibrium associated with the acceleration of the washing machine is:
[tex]\Sigma F = P -\mu_{k}\cdot m \cdot g = m\cdot a[/tex] (1)
Where:
[tex]P[/tex] - External force exerted on the washing machine, measured in newtons.
[tex]\mu_{k}[/tex] - Kinetic coefficient of friction, dimensionless.
[tex]m[/tex] - Mass, measured in kilograms.
[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.
[tex]a[/tex] - Net acceleration of the washing machine.
If we know that [tex]P = 380.8\,N[/tex], [tex]m = 37\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex] and [tex]\mu_{k} = 0.54[/tex], then the net acceleration experienced by the washing machine is:
[tex]a = \frac{P}{m}-\mu_{k}\cdot g[/tex]
[tex]a = \frac{380.8\,N}{37\,kg}-(0.54)\cdot \left(9.807\,\frac{m}{s^{2}} \right)[/tex]
[tex]a = 4.996\,\frac{m}{s^{2}}[/tex]
The correct answer is B.
Which of the following does not illustrate a complete circuit?
Answer:
I think A
Explanation:
because it dosn't have enough tools
What type of electric current does a power plant generate for use in your home? OA direct alternating OC. repeating OD straight
Answer:
Direct current
Explanation:
Because it cannot reverse, and it's optimum for usage by electric home appliances.
Unlike Alternating current which reverses, and can cause electric appliances to burn out.
A hot air balloon holds 7.40 x 107 liters of gas. In order for the hot air balloon to rise into the sky, it must be heated to 120°C. Once the balloon is up in the air, the air needs to be cooled in order for the balloon to land. If the temperature of the balloon is decreased to 40.0°C, what will the new volume of the gas be?
Remember to pay close attention to the units of temperature before beginning your calculations.
Answer:
2.467×10^7 litres
Explanation:
Using the formula V1/T1 = V2/T2
V1 and V2 are the initial and final volume respectively
T1 and T2 are their respective temperatures
Given
V1 = 7.4×10^7litres
T1 = 120°C
T2 = 40°C
Required
V2
From the formula
V2 = V1T2/T1
V2 = 7.4×10^7(40)/120
V2 = (7.4×10^7)/3
V2 = 2.467×10^7 litres
Hence the new volume of the gas will be 2.467×10^7 litres
A child pushes a 100 kg refrigerator with a force of 50 N, but the refrigerator does not move. Suppose the coefficient of static friction between the floor and the refrigerator is 0.4. What is the force due to friction in this scenario
Answer:
50 N
Explanation:
Since the refrigerator doesn’t move, that means the force of friction equals the amount of force the child exerts on the fridge. If the friction force were greater than the force by the child, the fridge would start accelerating towards the child. If it were less than the force the child exerted, the fridge would start accelerating away from the child. Therefore, the net force must be 0, in this case, the friction force is equal to the force the child exerted, for it to stay at rest (as Newton’s First Law stated).
I hope this helps! :)
A bus accelerates forward. If an apple were on the floor of the bus it would move forward.
A: True
B: False
Answer:
False
Explanation:
Since it is on the bus, it would not move forward because the outside acceleration cannot be considered.
Why does sound travel more quickly through a solid than through a liquid or a gas?
Answer:
things move quickly through a liquid
Explanation:
A car traveling with 500,000 J of kinetic energy is brought to a kinetic energy of
100,000 J in 12 seconds. What is the force acting on the car to accomplish this?
A:41,666.67
B:3x10^-5N
C:33,333.33N
D:8,333.33N
Answer:
33,333.33 N
Explanation:
Given that :
Initial kinetic energy = 500,000 J
Final kinetic energy = 100,000 J
Using the relation :
Force * time = change in momentum (Newton's law)
Force (F) * 0.12 = (500,000 - 100,000)
0.12F = 400,000 J
Force = (400,000 J) / 0.12s
Force = 33333.333
Force = 33,333.33 N
Which of the following best describes reflection?
a. Reflection is when waves bend around an obstacle.
b. Reflection is when waves bounce off a surface.
c. Reflection is when waves bend.
Reflection is when waves bounce off a surface this because I did it in 7th grade was my favorite unit to learn in school.
What is Reflection?When two different media come together at an a wavefront might change direction so that it returns to the first medium, which is known as reflection.
The reflection of light, sound, and water waves are typical examples. According to the law of reflection, the angle at which the wave incident on the surface equals the angle at which it is reflected for specular reflection (such as at a mirror).
Reflection produces echoes in acoustics and is used in sonar. It is crucial to the study of seismic waves in geology. Surface waves in bodies of water are used to observe reflection.
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A 1370-kg small aircraft accelerates along the runway from 7.4 m/s to 37.8 m/s in 5.20 seconds. Determine the net force acting upon the plane. (Assume that its engine/propeller makes no contributes to its forward motion)
Answer:
8009 N
Explanation:
Given that a 1370-kg small aircraft accelerates along the runway from 7.4 m/s to 37.8 m/s in 5.20 seconds. Determine the net force acting upon the plane. (Assume that its engine/propeller makes no contributes to its forward motion)
According to the definition of acceleration, acceleration is the change in velocity per time taken.
Acceleration a = ( 37.8 - 7.4 )/ 5.2
Acceleration a = 30.4 / 5.2
Acceleration a = 5.846 m/s^2
Force = mass × acceleration
Force = 1370 × 5.846
Force = 8,009 N
Therefore, the net force acting upon the plane is 8009 N. (Assume that its engine/propeller makes no contributes to its forward motion)
what are the harmful effects of drugs in the body?
Explanation:
causes hallucinations
causes lung cancer eg cigarettes
causes bad breath
damages the nervous system eg cocaine
Explanation:
Drug use can lead to an addiction. Effects of
drugs on the body can slowly destroy vital
systems and functions. Drug dependence can quickly begin to affect your psychological and physical health, and can also affect your work and social life.
hope it helps!
State three uses of dimensions.
Explanation:
answers.................
Explanation:
dimension are used for
1 we check the homogeneity of a physical equation
2 drive a possible formula for a physical problem
3 To find dimensions of physical constants or coefficients.
In a place covered by shadow of cloud sun cannot be seen . Explain with reasons .
Answer:
Because even though our eyes have a huge dynamic range (ability to pick out details in sharply lit and lesser lit areas simultaneously) than any camera, there's a limit.
When there's strong sunlight, your pupils contract and let less light in, which makes the shadows look darker.
When it's cloudy, your pupils widen and let more light in, which makes the shadows look less dark.
Do some experiments with a camera and you'll soon get the hang of it.
NOTE: Also test HDR (high dynamic range) photography, where the camera takes three or more pictures in quick succession, with different exposure settings, and combines them to get the most detail of both bright and dark areas. The result is more or less what we percieve.
A railroad car is pulled through the distance of 960 m by a train that did 578 kJ of work during this pull.
How much force did the train supply? (Show work)
Answer:
602.08 NExplanation:
The force supplied by the train can be found by using the formula
[tex]f = \frac{w}{d} \\ [/tex]
w is the workdone
d is the distance
From the question we have
[tex]f = \frac{578000}{960} \\ = 602.083333...[/tex]
We have the final answer as
602.08 NHope this helps you
The force supplied by the train is 602.1 N.
What is force?
This can be defined as the product of mass and the acceleration of a body.
To calculate the amount of force supplied by the train, we use the formula below.
Formula:
W = Fd................. Equation 1Where:
W = Work done by the trainF = Force supplied by the traind = DistanceMake F the subject of the equation
F = W/d........... Equation 2From the question,
Given:
W = 578 kJ = 578000 Jd = 960 mSubstitute these values into equation 2
F = 578000/960F = 602.1 NHence, The force supplied by the train is 602.1 N.
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Two identical peaches, Peach 1 and Peach 2, fall from a cliff at time t=0t=0t, equals, 0 from the same height. Peach 1 is dropped from rest, while Peach 2 is thrown horizontally.
Which graph best describes the vertical displacement of Peach 1 and 2 over time?
Assume the origin of the coordinate system to be the cliff edge.
Choose 1 answer:
Choose 1 answer:
(Choice A)
A
A graph is shown with the vertical axis labeled y and the horizontal axis labeled t. Two lines both start at the origin and slope downwards to the right. The solid line is straight while the dashed line has downward concavity.
(Choice B)
B
A graph is shown with the vertical axis labeled y and the horizontal axis labeled t. Two lines both start at the origin and slope downwards to the right. The dashed line is straight while the solid line has upward concavity.
(Choice C)
C
A graph is shown with the vertical axis labeled y and the horizontal axis labeled t. Two lines both start at the origin and slope downwards to the right with downward concavity. Both lines are coincident.
(Choice D)
D
A graph is shown with the vertical axis labeled y and the horizontal axis labeled t. Two lines both start at the origin and slope downwards to the right with downward concavity. The solid line is shallower than the dashed line.
(Choice E)
E
A graph is shown with the vertical axis labeled y and the horizontal axis labeled t. Two lines both start at the origin and slope downwards to the right with upward concavity. The dashed line is shallower than the solid line.
Report a problem
4 of 9
Answer: The correct answer is graph A.
Explanation:
See Khan Academy.
Answer: it C
Explanation:
In the following figure identify ‘A’ and ‘B’ which represents different colours of the spectrum. Why does this phenomenon occur?
Answer:
A is red
B is violet
Explanation:
A has a high penetration power hence greatest frequency and short wavelength in accordance to the diagram above.
The color with greatest frequency is red.
B has the least penetration power as it is greatly refracted in accordance to the diagram which shows that it has least frequency and high wavelength.
The color of least frequency is violet.
A(n) ____________ stretch is one done where antagonist muscles are used to stretch the muscles. But the _____________ stretch is one that is done that the muscle needs help from something or someone to stretch the muscle.
Answer: Dynamic - Static Flexibility
Explanation:
A machine that uses 200 w of power moves an object a distance of 15 m in 25 sec. Find
the force needed and the work done by this machine,
Answer:dummy
Explanation:
Dum dum
Two balloons are charged with an identical quantity and type of charge: -0.0025 C. They are held apart at a separation distance of 8 m. Determine the magnitude of the electrical force of repulsion between them.
Answer:
F = 878.9 N
Explanation:
The electrostatic force of attraction or repulsion is given by Coulomb's Law as follows:
F = kq₁q₂/r²
where,
F = Force pf repulsion between balloons = ?
k = Coulomb's Constant = 9 x 10⁹ N.m²/C²
q₁ = q₂ = magnitudes of 1st and 2nd charge = 0.0025 C
r = distance between balloons = 8 m
Therefore,
F = (9 x 10⁹ N.m²/C²)(0.0025 C)(0.0025 C)/(8 m)²
F = 878.9 N
The magnitude of the electrical force of repulsion between them is F = 878.9 N
Calculation of the magnitude of the electrical force:
Here we use Coulomb's Law
F = kq₁q₂/r²
Here,
F = Force of repulsion
k = Coulomb's Constant = 9 x 10⁹ N.m²/C²
q₁ = q₂ = magnitudes of 1st and 2nd charge = 0.0025 C
r = distance between balloons = 8 m
So,
F = (9 x 10⁹ N.m²/C²)(0.0025 C)(0.0025 C)/(8 m)²
F = 878.9 N
Hence, The magnitude of the electrical force of repulsion between them is F = 878.9 N
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Question 5 of 10
Why are magnetic materials attracted to magnets?
A. They become permanent magnets when they are in a magnetic
field,
B. They become temporary magnets when they are in a magnetic
field.
C. They are temporary magnets whether or not they are in a magnetic
field.
D. They are also attracted to Earth's magnetic field, which is always
present
Answer:
The answer is B
Explanation:
Trust
A Chevy Camaro drives straight off the top level off a parking garage at 13 m/s. If the car landed 90 meters away from the base of the parking garage, how high (height) was the top level?
a200.64
b234.64
c34.64
d134.64
Answer:
234.64 m
Explanation:
Using the formula for calculating range;
Range R = u√2H/g
u is the speed = 13m/s
H is the maximum height
g is the acceleration due to gravity = 9,8m/s²
R = 90m
Get the maximum height;
90 = 13√2H/9.8
90/13 = √2H/9.8
6.923 = √2H/9.8
square both sides
6.923² = 2H/9.8
469.698 = 2H
H = 469.698/2
H = 234.64
Hence the top level was 234.64 m high.
Please answer ASAP!!!! Which statement describes the factors that affect the force of a spring?
A. The spring force depends on the spring constant, and increases as displacement
increases
B. The spring force only depends on the spring constant
C. The spring force gets weaker as displacement increases, and is in the same
direction as the displacement
D. The spring force depends on gravity and friction
Answer:
d
Explanation:
the spring depends on gravity and friction
Identify the role of organisms in this food chain.
dragonfly
frog
grass
hawk
mushrooms
Answer:
the grass is the producer, the mushroom is the decomposer, the dragonfly is the primary consumer, the frog is the secondary, and the hawk is the tertiary consumer.
Explanation:
Hope this helps :)
Answer:
A. Frog
C. Hawk
D. Snake
Explanation:
I just took the test and these answers are right!