WorksheetsExam 3 Practice Set (Work, Power, Energy)
Total questions: 20
Worksheet time: 10mins
1. A 15 N force pulls a box horizontally for 6.0 m. What is the work done if the force makes a 25° angle above the horizontal?
82 J
90 J
60 J
120 J
A 3.2 kg mass falls freely from rest through 5.0 m. What is its final speed?
7.0 m/s
10.0 m/s
5.0 m/s
3.2 m/s
3. Which statement is false about mechanical work?
Mechanical work is done when a force moves an object in the direction of the force.
Mechanical work is measured in joules.
Mechanical work can be done without any movement of the object.
Mechanical work depends on both force and displacement.
A 1500 kg car accelerates from rest to 20 m/s. What is its change in kinetic energy?
300,000 J
15,000 J
600,000 J
30,000 J
5. A spring (k = 80 N/m) is stretched 0.30 m. The potential energy stored is:
3.6 J
2.4 J
1.8 J
4.8 J
6. A crane lifts a 250 kg crate vertically 12 m in 6.0 s. What is the average power output?
4,900 W
5,000 W
6,000 W
2,500 W
A 0.15 kg baseball has 75 J of kinetic energy. What is its speed?
32 m/s
10 m/s
50 m/s
20 m/s
If a car’s speed doubles, its kinetic energy:
quadruples
doubles
remains the same
triples
Calculate work done by the applied force.
Work = Force × Distance
Work = Mass × Acceleration
Work = Force / Area
Work = Power × Time
A spring stores 18 J when stretched 0.20 m. What is the spring constant?
450 N/m
180 N/m
225 N/m
900 N/m
A 5.0 kg rock slides down a frictionless incline of height 4.0 m. What is its speed at the bottom?
4.0 m/s
8.9 m/s
2.0 m/s
6.3 m/s
12. Which situation does not involve work (in the physics sense)?
Holding a heavy box without moving it
Pushing a box across the floor
Lifting a book onto a shelf
Pulling a sled along the ground
A 700 N person climbs 5.0 m up a ladder in 8.0 s. What is the average power output?
440 W
87.5 W
560 W
350 W
14. Two identical blocks slide on a frictionless surface. Block A moves at 4 m/s, Block B at 8 m/s. The kinetic energy of Block B is:
twice that of Block A
four times that of Block A
the same as Block A
half that of Block A
A 0.25 kg toy car compresses a spring by 0.15 m (k = 200 N/m). When released, what is its speed assuming no losses?
2.45 m/s
1.73 m/s
3.87 m/s
0.87 m/s
A 55 kg student runs up a 2.5 m high stairwell in 2.0 s. What is the power output?
680 W
275 W
110 W
340 W
A 2.0 kg block slides 3.0 m on a rough surface with μ = 0.25. Find work done by friction.
-14.7 J
-7.5 J
-9.8 J
-5.0 J
Which statement about power is true?
Power is the rate at which work is done.
Power is measured in meters per second.
Power is the same as energy.
Power cannot be calculated.
An 80 kg person on a stair-stepper lifts their weight through 0.25 m each step, doing 70 steps/min for 10 minutes. The total work done is:
1,372,000 J
137,200 J
13,720 J
1,372 J
A strongman exerts 1500 N on the side of a building. After 2 minutes, the building doesn't move. How much work did he do?
180,000 J
0 J
750 J
1500 J
