Power Review Quiz

What is the minimum power required for a conveyor to raise an 8.0 N box 4.0 m vertically in 8.0 s ?
1. 260 W
2. 32 W
3. 4.0 W
4. 64 W
Which is a unit of power ?
1. joule
2. joule/second
3. kilogram*meter/second
4. newton*meter2/second
A force of 10. N is required to keep an object moving at a constant speed of 5 m/s. The power used is
1. 0.5 W
2. 2 W
3. 50
4. 5 W
What is the maximum distance that a 60. W motor may vertically lift a 90. N weight in 7.5 s ?
1. 2.3 m
2. 5.0 m
3. 140 m
4. 1100 m
A weightlifter lifts a 2000 N weight a vertical distance of 0.5 m in 0.1 s. What is the power output ?
1. 0.0001 W
2. 0.0004 W
3. 10,000 W
4. 40,000 W
Which term is a unit of power?
1. Joule
2. Newton
3. Watt
4. Newton*meter
As the power of a machine is increased, the time required to move an object a fixed distance
1. increases
2. decreases
3. increases then decreases
4. remains the same
A force of 70 N must be exerted to keep a car moving with a constant speed of 10 m/s. What is the rate at which energy must be supplied ?
1. 0.14 W
2. 7.0 W
3. 700 W
4. 7000 W
A 3.0-kg block is initially at rest on a frictionless, horizontal surface. The block is moved 8.0 m in 2.0 sec by the application of a 12 N horizontal force. What is the average power developed while moving the block?
1. 24 W
2. 48 W
3. 32 W
4. 96 W
A 40.-kilogram student runs up a staircase to a floor that is 5.0 meters higher than her starting point in 7.0 seconds. The student's power output is
1. 29 W
2. 1.4x10^4 W
3. 280 W
4. 1.4x10^3 W