Chapter 7: Work Energy and Simple Machines — Online MCQ Test
SCIENCE · Grade 9 · CBSE(NCERT)
Practice Chapter 7: Work Energy and Simple Machines with a free chapter-wise online MCQ test.
This chapter covers: Work Energy Kinetic Energy Potential Energy Mechanical Energy Power Conservation of Energy Lever Pulley Inclined Plane Simple Machines Understanding energy transformation work powe....
AI-generated questions from basic to board-exam level, with instant results and explanations.
Chapter 7: Work Energy and Simple Machines — Important Questions & Answers
Which of the following is the SI unit of work?
- A. Joule
- B. Watt
- C. Newton
- D. Pascal
Answer: A. Joule
Work is measured in joules (J) in the SI system. One joule is the work done when a force of 1 newton moves an object by 1 metre in the direction of the force.
Work is measured in joules (J) in the SI system. One joule is the work done when a force of 1 newton moves an object by 1 metre in the direction of the force.
An object has kinetic energy because it is:
- A. at rest
- B. moving
- C. made of metal
- D. placed on a table
Answer: B. moving
Kinetic energy is the energy possessed by a body due to its motion. If an object is moving, it has kinetic energy.
Kinetic energy is the energy possessed by a body due to its motion. If an object is moving, it has kinetic energy.
A force of 5 N moves an object by 2 m in the same direction. What is the work done?
- A. 2.5 J
- B. 7 J
- C. 10 J
- D. 20 J
Answer: C. 10 J
Work done = Force × displacement = 5 × 2 = 10 J, when force and displacement are in the same direction.
Work done = Force × displacement = 5 × 2 = 10 J, when force and displacement are in the same direction.
Which one of the following has the greatest kinetic energy, if all have the same mass?
- A. A stationary bicycle
- B. A bicycle moving slowly
- C. A bicycle moving fast
- D. A bicycle standing on a slope
Answer: C. A bicycle moving fast
Kinetic energy depends on speed. For the same mass, a faster moving object has greater kinetic energy.
Kinetic energy depends on speed. For the same mass, a faster moving object has greater kinetic energy.
A machine is 100% efficient. Which statement must be true?
- A. Output work is greater than input work
- B. Some energy is lost as heat
- C. Input work equals output work
- D. The machine does not require any force
Answer: C. Input work equals output work
A 100% efficient machine has no energy loss, so the input work is equal to the output work. In real life, no machine is perfectly efficient.
A 100% efficient machine has no energy loss, so the input work is equal to the output work. In real life, no machine is perfectly efficient.