Chapter 4: Work Energy and Power — Online MCQ Test
PHYSICS · CLASS 11th · Tamil Nadu State Board
Practice Chapter 4: Work Energy and Power with a free chapter-wise online MCQ test.
This chapter covers: Focusing on mechanical energetics this chapter details work done by constant and variable forces work-energy theorem potential kinetic energy. Students examine conservative non-con....
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Chapter 4: Work Energy and Power — Important Questions & Answers
What is the SI unit of work?
- A. Joule
- B. Watt
- C. Newton
- D. Pascal
Answer: A. Joule
Work is defined as force multiplied by displacement, and its SI unit is the Joule (J).
Work is defined as force multiplied by displacement, and its SI unit is the Joule (J).
Which of the following is a scalar quantity?
- A. Force
- B. Work
- C. Displacement
- D. Momentum
Answer: B. Work
Work is the dot product of force and displacement vectors, resulting in a scalar quantity.
Work is the dot product of force and displacement vectors, resulting in a scalar quantity.
If the velocity of a body is doubled, its kinetic energy becomes:
- A. Double
- B. Four times
- C. Half
- D. Unchanged
Answer: B. Four times
Kinetic energy is proportional to the square of velocity (KE = 1/2 mv^2), so doubling v quadruples the KE.
Kinetic energy is proportional to the square of velocity (KE = 1/2 mv^2), so doubling v quadruples the KE.
A particle of mass m moves with constant speed v on a circular path of radius r. The work done in one complete revolution is:
- A. mv^2/r * 2*pi*r
- B. mv^2/r
- C. Zero
- D. 2*pi*r*mv
Answer: C. Zero
Since the force is always perpendicular to displacement at every point, the total work done over a closed loop is zero.
Since the force is always perpendicular to displacement at every point, the total work done over a closed loop is zero.
A 10 kg mass moving at 5 m/s collides with a 5 kg mass at rest. If they stick together, what is the loss in kinetic energy?
- A. 25 J
- B. 41.67 J
- C. 83.33 J
- D. 125 J
Answer: B. 41.67 J
Calculate initial KE, find final velocity using momentum conservation, calculate final KE, and find the difference.
Calculate initial KE, find final velocity using momentum conservation, calculate final KE, and find the difference.