HEC USAT-E (Pre-Engineering) Physics Work & Energy — Set 2

HEC USAT-E (Pre-Engineering) Physics Work & Energy — Set 2

1. Question 1

   Q1. A force of 5 N acts on a body, displacing it by 2 m. What is the work done?

   • A) 5 J
   • B) 10 J
   • C) 15 J
   • D) 20 J

   Answer: 10 J

   Explanation: Work done = F * d = 5 * 2 = 10 J, using the formula for work done.

2. Question 2

   Q2. A body of mass 1 kg is lifted to a height of 2 m. What is the potential energy gained?

   • A) 10 J
   • B) 20 J
   • C) 19.6 J
   • D) 15 J

   Answer: 19.6 J

   Explanation: Potential energy = mgh = 1 * 9.8 * 2 = 19.6 J, using the formula for potential energy.

3. Question 3

   Q3. A spring of spring constant 100 N/m is compressed by 0.1 m. What is the energy stored?

   • A) 0.1 J
   • B) 0.5 J
   • C) 1 J
   • D) 5 J

   Answer: 0.5 J

   Explanation: Energy stored = 1/2 kx² = 1/2 * 100 * 0.1² = 0.5 J, using the formula for energy stored in a spring.

4. Question 4

   Q4. A body is moving in a circular path. What is the work done by the centripetal force?

   • A) Positive
   • B) Negative
   • C) Zero
   • D) Maximum

   Answer: Zero

   Explanation: Work done by centripetal force is zero as it is perpendicular to displacement, using the concept of work done.

5. Question 5

   Q5. A 5 kg block is moving with 2 m/s velocity. What is its momentum?

   • A) 5 kg m/s
   • B) 10 kg m/s
   • C) 15 kg m/s
   • D) 20 kg m/s

   Answer: 10 kg m/s

   Explanation: Momentum = mv = 5 * 2 = 10 kg m/s, using the formula for momentum.

6. Question 6

   Q6. A body of mass 2 kg is moving with 3 m/s velocity. What is its kinetic energy?

   • A) 6 J
   • B) 9 J
   • C) 12 J
   • D) 15 J

   Answer: 9 J

   Explanation: Kinetic energy = 1/2 mv² = 1/2 * 2 * 3² = 9 J, using the formula for kinetic energy.

7. Question 7

   Q7. A spring is stretched by 0.2 m. If its spring constant is 50 N/m, what is the energy stored?

   • A) 0.5 J
   • B) 1 J
   • C) 1.5 J
   • D) 2 J

   Answer: 1 J

   Explanation: Energy stored = 1/2 kx² = 1/2 * 50 * 0.2² = 1 J, using the formula for energy stored in a spring.

8. Question 8

   Q8. A body is lifted to a height of 5 m. If its mass is 3 kg, what is the potential energy gained?

   • A) 147 J
   • B) 150 J
   • C) 100 J
   • D) 120 J

   Answer: 147 J

   Explanation: Potential energy = mgh = 3 * 9.8 * 5 = 147 J, using the formula for potential energy.

9. Question 9

   Q9. A force of 20 N acts on a body, displacing it by 3 m. What is the work done?

   • A) 50 J
   • B) 60 J
   • C) 65 J
   • D) 70 J

   Answer: 60 J

   Explanation: Work done = F * d = 20 * 3 = 60 J, using the formula for work done.

10. Question 10

    Q10. A body of mass 4 kg is moving with 2 m/s velocity. What is its kinetic energy?

    • A) 4 J
    • B) 6 J
    • C) 8 J
    • D) 10 J

    Answer: 8 J

    Explanation: Kinetic energy = 1/2 mv² = 1/2 * 4 * 2² = 8 J, using the formula for kinetic energy.

11. Question 11

    Q11. A spring of spring constant 200 N/m is compressed by 0.2 m. What is the energy stored?

    • A) 2 J
    • B) 4 J
    • C) 6 J
    • D) 8 J

    Answer: 4 J

    Explanation: Energy stored = 1/2 kx² = 1/2 * 200 * 0.2² = 4 J, using the formula for energy stored in a spring.

12. Question 12

    Q12. A body is moving in a circular path of radius 2 m. If its mass is 1 kg and velocity is 4 m/s, what is its kinetic energy?

    • A) 4 J
    • B) 6 J
    • C) 8 J
    • D) 10 J

    Answer: 8 J

    Explanation: Kinetic energy = 1/2 mv² = 1/2 * 1 * 4² = 8 J, using the formula for kinetic energy.

13. Question 13

    Q13. A force of 15 N acts on a body for 3 s. What is the impulse?

    • A) 40 Ns
    • B) 45 Ns
    • C) 50 Ns
    • D) 55 Ns

    Answer: 45 Ns

    Explanation: Impulse = F * t = 15 * 3 = 45 Ns, using the formula for impulse.

14. Question 14

    Q14. A body of mass 2 kg is lifted to a height of 4 m. What is the potential energy gained?

    • A) 70 J
    • B) 78.4 J
    • C) 80 J
    • D) 90 J

    Answer: 78.4 J

    Explanation: Potential energy = mgh = 2 * 9.8 * 4 = 78.4 J, using the formula for potential energy.

15. Question 15

    Q15. A spring is stretched by 0.1 m. If its spring constant is 100 N/m, what is the energy stored?

    • A) 0.2 J
    • B) 0.5 J
    • C) 1 J
    • D) 2 J

    Answer: 0.5 J

    Explanation: Energy stored = 1/2 kx² = 1/2 * 100 * 0.1² = 0.5 J, using the formula for energy stored in a spring.

16. Question 16

    Q16. A body is moving with 5 m/s velocity. If its mass is 3 kg, what is its kinetic energy?

    • A) 35 J
    • B) 37.5 J
    • C) 40 J
    • D) 45 J

    Answer: 37.5 J

    Explanation: Kinetic energy = 1/2 mv² = 1/2 * 3 * 5² = 37.5 J, using the formula for kinetic energy.

17. Question 17

    Q17. A force of 25 N acts on a body, displacing it by 2 m. What is the work done?

    • A) 40 J
    • B) 50 J
    • C) 60 J
    • D) 70 J

    Answer: 50 J

    Explanation: Work done = F * d = 25 * 2 = 50 J, using the formula for work done.

18. Question 18

    Q18. A body of mass 1 kg is moving with 6 m/s velocity. What is its kinetic energy?

    • A) 16 J
    • B) 18 J
    • C) 20 J
    • D) 22 J

    Answer: 18 J

    Explanation: Kinetic energy = 1/2 mv² = 1/2 * 1 * 6² = 18 J, using the formula for kinetic energy.

19. Question 19

    Q19. A force of 10 N acts on a body, displacing it by 5 m. What is the work done?

    • A) 50 J
    • B) 20 J
    • C) 10 J
    • D) 0 J

    Answer: 50 J

    Explanation: Work done = F * d = 10 * 5 = 50 J, using the formula for work done.

20. Question 20

    Q20. A 5 kg block is lifted to a height of 2 m. What is the potential energy gained?

    • A) 100 J
    • B) 50 J
    • C) 98 J
    • D) 20 J

    Answer: 98 J

    Explanation: Potential energy = mgh = 5 * 9.8 * 2 = 98 J, using the formula for potential energy.