A force must be applied to an object to make it move and the force has to be in the same direction as the movement.
100
What are the two variables that kinetic energy is dependent upon?
Mass and velocity
100
What is the equation for gravitational potential energy
PE=mgh
100
A ball is sitting on a ledge. What is the kinetic energy of the ball if the potential energy it had before it was dropped was 30 J.
30 J
100
To pull a weed out of a garden, you can apply a force of 50 N to the shovel. The shovel applies a force of 600 N to the weed. What is the actual mechanical advantage of the shovel?
12
200
How much work is being done if it takes 5 Newtons to push a cart down a 15 meter hallway?
75 J
200
Kinetic energy is the energy of __________.
movement
200
What potential energy is gained by a 150 kg climber that scales a 100 m cliff.
147,000 J
200
Where would a swing have the most potential energy?
At the top of the swing
200
An inclined plane with one or two sloping sides is a _______.
wedge
300
If a neighbor pushes a lawnmower four times as far as you do but exerts only half the force, who has done more work?
The neighbor
300
What is the amount of kinetic energy of a 65kg sprinter running at 8.4 m/s?
2293.2 J
300
What is the loss in potential energy of an 8kg apple that falls from a 5 m high tree branch.
392 J
300
Why can a machine never be 100% efficient?
because of heat and friction
300
What is the IMA of a pulley with 2 ropes that uses 50 N to lift a 100 N load.
2
400
A set of pulleys is used to lift a piano weighing 1000 newtons. The piano is lifted 3 meters in 60 seconds. How much power is used?
50 W
400
What is the speed of a 35000 kg train that has a kinetic energy of 282,000 J.
4.01 m/s
400
Determine the gravitational potential energy of a guillotine if the mouton (the weighted blade) has a mass of 40 kg and is raised 2.5 m above the neck of the condemned.
980 J
400
What are two ways machines make work easier?
increase force or change direction
400
How does a ramp make lifting a heavy object easier?
Less force is needed to move the object over a longer distance.
500
Explain why you do the same amount of work going up and down stairs but your power can change.
Your weight (force) and distance of the stairs will not change. However, you can change how fast you do it.
500
In a pendulum, where does the pendulum have the most kinetic energy?
at the bottom of the swing
500
Potential energy is __________ energy.
stored
500
What is an example of a 2nd class lever?
wheelbarrow
500
A lever moves around a fixed point called a ___________.