Chapter 10 PHYSICAL SCIENCE : Work and Energy — Online MCQ Test
SCIENCE · CLASS 9th · Andhra State Board
Practice Chapter 10 PHYSICAL SCIENCE : Work and Energy with a free chapter-wise online MCQ test.
This chapter covers: This chapter details scientific concept of work kinetic energy potential energy law of conservation of energy and rate of doing work power..
AI-generated questions from basic to board-exam level, with instant results and explanations.
Chapter 10 PHYSICAL SCIENCE : Work and Energy — Important Questions & Answers
What is the SI unit of work?
- A. Joule
- B. Watt
- C. Newton
- D. Pascal
Answer: A. Joule
The SI unit of work is Joule (J), defined as the work done when a force of 1 Newton displaces an object by 1 meter.
The SI unit of work is Joule (J), defined as the work done when a force of 1 Newton displaces an object by 1 meter.
Which of the following is a unit of power?
- A. Joule/second
- B. Joule-meter
- C. Newton/meter
- D. Kilowatt-hour
Answer: A. Joule/second
Power is defined as the rate of doing work, so its unit is Joule per second, which is also known as a Watt.
Power is defined as the rate of doing work, so its unit is Joule per second, which is also known as a Watt.
A girl is carrying a school bag on her back and walking on a leveled road. What is the work done against gravity?
- A. Positive
- B. Negative
- C. Zero
- D. Infinite
Answer: C. Zero
Since the displacement is horizontal and the force of gravity acts vertically downwards, the angle between them is 90 degrees, resulting in zero work.
Since the displacement is horizontal and the force of gravity acts vertically downwards, the angle between them is 90 degrees, resulting in zero work.
A crane lifts a load of 1000 N to a height of 10 m in 20 seconds. What is the power of the crane?
- A. 50 W
- B. 500 W
- C. 2000 W
- D. 10000 W
Answer: B. 500 W
Power = Work / Time = (Force * Distance) / Time = (1000 * 10) / 20 = 500 Watts.
Power = Work / Time = (Force * Distance) / Time = (1000 * 10) / 20 = 500 Watts.
If the angle between force and displacement is 180 degrees, the work done is:
- A. Positive
- B. Negative
- C. Zero
- D. Maximum
Answer: B. Negative
Work = F d cos(theta). If theta is 180 degrees, cos(180) = -1, making the work done negative.
Work = F d cos(theta). If theta is 180 degrees, cos(180) = -1, making the work done negative.