Chapter Exam

Chapter 7: Work Energy and Simple Machines — Online MCQ Test

Q: Which of the following is the SI unit of work?

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.

Q: An object has kinetic energy because it is:

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.

Q: A force of 5 N moves an object by 2 m in the same direction. What is the work done?

Answer: C. 10 J — Work done = Force × displacement = 5 × 2 = 10 J, when force and displacement are in the same direction.

Q: Which one of the following has the greatest kinetic energy, if all have the same mass?

Answer: C. A bicycle moving fast — Kinetic energy depends on speed. For the same mass, a faster moving object has greater kinetic energy.

Q: A machine is 100% efficient. Which statement must be true?

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.

SCIENCE · Grade 9 · CBSE(NCERT)

Practice Chapter 7: Work Energy and Simple Machines with a free chapter-wise online MCQ test for CBSE(NCERT) Grade 9 SCIENCE. 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.

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Chapter 7: Work Energy and Simple Machines — Important Questions & Answers (FAQ)

Frequently asked questions from CBSE(NCERT) Grade 9 SCIENCE — Chapter 7: Work Energy and Simple Machines, with answers and explanations. These are sample questions; the exam has its own separate question set.

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.

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.

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.

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.

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.

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