What's the variable?
Work & Power
????
Conservation of Energy
Simple Machines
100
In this image, 200 N is the value for what variable?
a. Work
b. Force
c. Potential Energy
d. Power
b. Force
100
The person in the image pushes the box with 15 N of force 25 meters to the right. How much work does he do on the box? (Include the unit for work in your answer)
375 Joules
100
What equation should you use to find the length of the ramp?
MA = Din / Dout
100
How much gravitational potential energy does the ball have in this image? Include the unit for energy in your answer.
490 Joules
GPE = m * 9.8 * h
GPE = 1 * 9.8 * 50
100
If someone uses a screwdriver to pry open a can of paint, what kind of simple machine is this?
Lever
200
In this image, Δy is the same as what variable?
a. velocity
b. Force
c. Work
d. displacement
d. displacement
200
The boy in the picture pushes the crate 15 meters and does 1,125 Joules of work. With how much force did he push on the box?
W = F * d
1,125 = F * 15
75 N = F
200
The velocity of the ball at point A is 15 m/s. Point D is 11.5 meters high. How much mechanical kinetic energy does the ball have at point D?
0 Joules
(The ball's velocity is 0 m/s at its highest point. If v=0, then MKE=0.)
200
At what two points does the ball have the same amount of mechanical kinetic energy?
A & C
200
At which point should the person push on in order to exert the least amount of force to lift the load?
F2 or F1?
F2
(The greater the input displacement, the less input force is required.)
300
What is the output force (Fout) in this scenario?
150 Newtons (the weight of the load)
300
The person in the image pushes on the box with 12 N of force to make it move 5 meters in 3 seconds. What is the person's power output? Include the unit for power in your answer
P = F * d / t
P = 12 * 5 / 3
P = 20 Watts
300
Jay does 400 J of work when they do one push-up. If they do 5 push-ups in 10 seconds, what is their power output?
Total work = 400 J * 5 = 2000 J
P = W / t
P = 2000 / 10
P = 200 Watts
300
At which of the three points does the roller coaster have the greatest velocity?
Point B
300
To open this vault, you must turn the dial. When you turn the dial, it spins a rod inside the door, which unlatches the lock.
The circumference of the dial is 1.2 meters. The circumference of the rod is 0.2 meters. What is the MA of this simple machine?
MA = Din / Dout
MA = 1.2 / 0.2
MA = 6
400
What is the value of Dout?
Dout = 0.5 meters
400
Tom raises a 45 N box 2 meters by lifting it straight up. Jim raises a 45 N box 2 meters by pushing it up a ramp. Who did more work?
a. Tom b. Jim c. Same
C. They did the same amount of work
400
At a shipping dock, a crane applies 1,500 N of force to lift a cargo container. It takes 4 seconds to lift the cargo from the ground to a height of 20 meters. What is the crane's power output? Include the unit for power in your answer
P = F * d / t
P = 1,500 * 20 / 4
P = 7,500 Watts
400
At which point or points along the pendulum's path does it have the most mechanical kinetic energy?
Point 3
400
The image below shows a socket wrench. The socket fits around the head of nut. When someone turns the handle of the wrench, the socket applies a force to the nut to unscrew it.
If someone wanted to unscrew a nut with the maximum amount of force possible, should the hold the handle at point A or Point B?
Point B
Holding the handle at Point B makes the input displacement greater than it would be if you held the handle at Point A. This means more work is being done, which means the socket will apply a greater amount of force to the nut.
500
The image below shows a crank that is used to lift a bucket out of a well. In this image, 0.8 meters is the value of what variable?
a. Fin
b. Fout
c. Din
d. Dout
0.8 meters = Din
500
Person A and Person B both pull their wagons 20 meters in 30 seconds.
Who has the greater power output?
A. Person A B. Person B C. Same
Person B
Person B had to exert more force, which means they did more work in the same amount of time.
500
The soccer ball in the image has an average mass and is traveling at an average velocity for a penalty kick in soccer. Which would result in a greater increase in the ball's mechanical kinetic energy?
a. increasing the mass by 1 kg
b. increasing the velocity by 1 m/s
c. both would result in the same increase in MKE
b. increasing the velocity by 1 m/s
MKE = 1/2 * m * v2
Since velocity is squared, any increase in velocity will have a great effect on MKE than an equal increase in mass
500
At which point or points does the pendulum have the lowest velocity?
1 & 4 
500
What will happen to this lever?
A. It will balance
B. The left side will fall down
C. The right side will fall down
C. The right side will fall down.
More work is done on the right side than on the left side. (W=F*d)