This is a BYU online Energy Physical Science Quiz and I've read the material. I'm just not seeming to pick it up. If you could help in any way; whether it be by give me the answers or explaining the formulas needed to solve some of these I'd be really grateful. Thank you.
1. A 20 N constant horizontal force is applied to a 5 kg box. As a result, the box moves 10 m to the right. How much work is done by this force?
1. 200 N•m
2. 100 N•m
3. 30 N•m
4. 25 N•m
5. 2 N•m
2. A 40 N force is applied vertically to lift an object 2 m. How much work is done by this force?
1. 80 N•m
2. 60 N•m
3. 42 N•m
4. 38 N•m
5. 20 N•m
3. A spring has a spring constant of 30 N/m. How much force will the spring exert if it is stretched 0.5 m?
1. 60 N
2. 30 N
3. 15 N
4. 7.5 N
5. 0.5 N
4. A spring stretches 1.5 meters when a force of 60 N is applied to it. What is the spring constant?
1. 90 N/m
2. 60 N/m
3. 45 N/m
4. 40 N/m
5. 30 N/m
5. A spring is observed to exert a force of 100 N when it is stretched 4 m. How much work is done to stretch this spring 4 m?
1. 400 N•m
2. 200 N•m
3. 100 N•m
4. 50 N•m
5. 25 N•m
For questions 6–10, identify the source of energy and the final energy in each energy transformations.
6. a flashlight
1. source: chemical -> final: kinetic
2. source: electrical -> final: chemical
3. source: chemical -> final: light
4. source: light -> final: chemical
5. source: heat -> final: light
7. driving a car
1. source: chemical -> final: kinetic
2. source: nuclear -> final: kinetic
3. source: chemical -> final: heat
4. source: electrical -> final: heat
5. source: chemical -> final: electrical
8. a candle
1. source: light -> final: kinetic
2. source: chemical -> final: light
3. source: chemical -> final: electric
4. source: light -> final: chemical
5. source: chemical -> final: kinetic
9. a campfire
1. source: heat -> final: kinetic
2. source: chemical -> final: kinetic
3. source: chemical -> final: electric
4. source: heat -> final: chemical
5. source: chemical -> final: heat
10. a solar-powered calculator
1. source: chemical -> final: light
2. source: electrical -> final: light
3. source: light -> final: electrical
4. source: chemical -> final: electrical
5. source: light -> final: kinetic
11. A 75 kg student stands at the top of a 20 m tall building. How much gravitational potential energy does this student possess?
1. 1500 J
2. 15,000 J
3. 150 J
4. 95 J
5. 3.75 J
12. A 0.050 kg bullet travels at 300 m/s. How much kinetic energy does it have?
1. 7.5 J
2. 15 J
3. 2250 J
4. 4500 J
5. 6000 J
13. When a car is moving up a hill, the engine stalls. Which of the following bar graphs could represent the car while it is still moving up the hill? (Assume that there is no friction and therefore no dissipated energy.)
1.
2.
3.
4.
5.
14. A 2000 kg truck is moving at 5 m/s at the top of a 10 m hill. How much total mechanical energy does the truck have?
1. 225,000 J
2. 200,000 J
3. 175,000 J
4. 125,000 J
5. 25,000 J
15. A spring with a spring constant of 45 N/m is stretched 3 m. How much elastic potential energy is now stored in the spring?
1. 405 J
2. 202.5 J
3. 135 J
4. 67.5 J
5. 15 J
16. A 2 kg ball sits at the top of a 3.2 m hill. How fast does it move at the bottom of the hill if there is no dissipated energy?
1. 10 m/s
2. 8 m/s
3. 20 m/s
4. 6.4 m/s
5. 2 m/s
17. A 100 kg cart is moving at 8 m/s across a horizontal surface. It collides with a safety spring and comes to a stop after compressing the spring 4 meters. What is the spring constant of the spring?
1. 6400 N/m
2. 3200 N/m
3. 1600 N/m
4. 800 N/m
5. 400 N/m
18. A 0.040 kg bullet is fired straight up with a velocity of 250 m/s. If 1,000 J of energy is dissipated by air resistance, how high will the bullet go?
1. 625 m
2. 250 m
3. 1,000 m
4. 3,125 m
5. 1,250 m
19. A professional baseball pitcher can throw a baseball (mass = 0.14 kg) at a speed of 100 miles per hour (about 45 m/s). If he throws it straight up, how high will it go? (Assume no energy is dissipated.)
1. A 20 N constant horizontal force is applied to a 5 kg box. As a result, the box moves 10 m to the right. How much work is done by this force?
1. 200 N•m
2. 100 N•m
3. 30 N•m
4. 25 N•m
5. 2 N•m
2. A 40 N force is applied vertically to lift an object 2 m. How much work is done by this force?
1. 80 N•m
2. 60 N•m
3. 42 N•m
4. 38 N•m
5. 20 N•m
3. A spring has a spring constant of 30 N/m. How much force will the spring exert if it is stretched 0.5 m?
1. 60 N
2. 30 N
3. 15 N
4. 7.5 N
5. 0.5 N
4. A spring stretches 1.5 meters when a force of 60 N is applied to it. What is the spring constant?
1. 90 N/m
2. 60 N/m
3. 45 N/m
4. 40 N/m
5. 30 N/m
5. A spring is observed to exert a force of 100 N when it is stretched 4 m. How much work is done to stretch this spring 4 m?
1. 400 N•m
2. 200 N•m
3. 100 N•m
4. 50 N•m
5. 25 N•m
For questions 6–10, identify the source of energy and the final energy in each energy transformations.
6. a flashlight
1. source: chemical -> final: kinetic
2. source: electrical -> final: chemical
3. source: chemical -> final: light
4. source: light -> final: chemical
5. source: heat -> final: light
7. driving a car
1. source: chemical -> final: kinetic
2. source: nuclear -> final: kinetic
3. source: chemical -> final: heat
4. source: electrical -> final: heat
5. source: chemical -> final: electrical
8. a candle
1. source: light -> final: kinetic
2. source: chemical -> final: light
3. source: chemical -> final: electric
4. source: light -> final: chemical
5. source: chemical -> final: kinetic
9. a campfire
1. source: heat -> final: kinetic
2. source: chemical -> final: kinetic
3. source: chemical -> final: electric
4. source: heat -> final: chemical
5. source: chemical -> final: heat
10. a solar-powered calculator
1. source: chemical -> final: light
2. source: electrical -> final: light
3. source: light -> final: electrical
4. source: chemical -> final: electrical
5. source: light -> final: kinetic
11. A 75 kg student stands at the top of a 20 m tall building. How much gravitational potential energy does this student possess?
1. 1500 J
2. 15,000 J
3. 150 J
4. 95 J
5. 3.75 J
12. A 0.050 kg bullet travels at 300 m/s. How much kinetic energy does it have?
1. 7.5 J
2. 15 J
3. 2250 J
4. 4500 J
5. 6000 J
13. When a car is moving up a hill, the engine stalls. Which of the following bar graphs could represent the car while it is still moving up the hill? (Assume that there is no friction and therefore no dissipated energy.)
1.
2.
3.
4.
5.
14. A 2000 kg truck is moving at 5 m/s at the top of a 10 m hill. How much total mechanical energy does the truck have?
1. 225,000 J
2. 200,000 J
3. 175,000 J
4. 125,000 J
5. 25,000 J
15. A spring with a spring constant of 45 N/m is stretched 3 m. How much elastic potential energy is now stored in the spring?
1. 405 J
2. 202.5 J
3. 135 J
4. 67.5 J
5. 15 J
16. A 2 kg ball sits at the top of a 3.2 m hill. How fast does it move at the bottom of the hill if there is no dissipated energy?
1. 10 m/s
2. 8 m/s
3. 20 m/s
4. 6.4 m/s
5. 2 m/s
17. A 100 kg cart is moving at 8 m/s across a horizontal surface. It collides with a safety spring and comes to a stop after compressing the spring 4 meters. What is the spring constant of the spring?
1. 6400 N/m
2. 3200 N/m
3. 1600 N/m
4. 800 N/m
5. 400 N/m
18. A 0.040 kg bullet is fired straight up with a velocity of 250 m/s. If 1,000 J of energy is dissipated by air resistance, how high will the bullet go?
1. 625 m
2. 250 m
3. 1,000 m
4. 3,125 m
5. 1,250 m
19. A professional baseball pitcher can throw a baseball (mass = 0.14 kg) at a speed of 100 miles per hour (about 45 m/s). If he throws it straight up, how high will it go? (Assume no energy is dissipated.)