Work Energy and Power Practice Questions
Class 11 · Physics · 859 free MCQs with instant results and detailed explanations.
859
Total
440
Easy
317
Medium
102
Hard
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Topics in Work Energy and Power
Work
120
Kinetic Energy
123
Power
114
Collisions
170
Conservation of Energy
151
Potential Energy
181
Sample Questions from Work Energy and Power
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
What is the work done by a force that acts on an object moving in the same direction as the force?
A.
Positive
B.
Negative
C.
Zero
D.
Undefined
Show Answer & Explanation
Correct Answer: A
When a force acts in the same direction as the displacement, the work done is positive.
Q2
Easy
Which of the following statements is true about work done when an object moves in a circular path under the influence of a radial force?
A.
Work is positive
B.
Work is negative
C.
Work is zero
D.
Work is undefined
Show Answer & Explanation
Correct Answer: C
When an object moves in a circular path, the radial force acts perpendicular to the direction of motion, resulting in zero work.
Q3
Easy
What happens to the work done if the angle between the force and displacement is 180 degrees?
A.
Work becomes positive
B.
Work becomes negative
C.
Work becomes zero
D.
Work is undefined
Show Answer & Explanation
Correct Answer: B
When the angle is 180 degrees, the force acts in the opposite direction to displacement, making the work done negative.
Q4
Medium
If 200 J of work is done to lift an object vertically, what is the increase in potential energy of the object?
A.
200 J
B.
100 J
C.
400 J
D.
50 J
Show Answer & Explanation
Correct Answer: A
The work done against gravity is converted into potential energy. Therefore, the increase in potential energy is equal to the work done, which is 200 J.
Q5
Medium
An object is pushed with a force of 15 N at an angle of 30 degrees to the horizontal for 4 m. What is the work done by the force?
A.
30 J
B.
60 J
C.
45 J
D.
75 J
Show Answer & Explanation
Correct Answer: C
Work done = F à d à cos(Ξ). Here, Work = 15 N à 4 m à cos(30°) = 15 à 4 à â3/2 = 45 J.
Q6
Medium
Which of the following scenarios represents negative work?
A.
Car accelerating forward
B.
Box pushed uphill
C.
Friction acting on a sliding object
D.
Object lifted upwards
Show Answer & Explanation
Correct Answer: C
Negative work occurs when the force applied is opposite to the direction of motion, such as friction acting against the sliding object.
Q7
Medium
If an object is moved in a circular path with a constant speed, what is the work done on the object?
A.
Positive
B.
Negative
C.
Zero
D.
Depends on speed
Show Answer & Explanation
Correct Answer: C
When an object moves in a circular path with constant speed, the direction of the force is perpendicular to the displacement, so the work done is zero.
Q8
Hard
If a body is moving in a circular path at a constant speed, is work being done on the body? Why or why not?
A.
Yes, because of centripetal force
B.
No, because displacement is zero
C.
Yes, because kinetic energy is increasing
D.
No, because force is perpendicular to displacement
Show Answer & Explanation
Correct Answer: D
In uniform circular motion, the centripetal force acts perpendicular to the direction of motion, resulting in no work done as work is defined by W = F à d à cos(Ξ) and Ξ = 90°.
Q9
Hard
A boy pushes a stationary car with a force of 400 N for 10 seconds. If the car doesn't move, how much work is done?
A.
4000 J
B.
0 J
C.
100 J
D.
40 J
Show Answer & Explanation
Correct Answer: B
Work done is zero because the object does not move, regardless of the force applied. W = F Ã d, and since d = 0, W = 0 J.
Q10
Hard
A car travels 100 m while accelerating uniformly from rest to a speed of 20 m/s. What is the work done on the car?
A.
2000 J
B.
500 J
C.
1000 J
D.
400 J
Show Answer & Explanation
Correct Answer: A
Using the work-energy theorem, W = ÎK.E. = (1/2)mv². First, find mass using F = ma: a = (v - u)/t = (20 - 0)/t, where t is time. Then, W = 2000 J.
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Work Energy and Power â Class 11 Physics Practice Questions Online
This page contains 859 practice MCQs for the chapter Work Energy and Power in Class 11 Physics. The questions are organized by difficulty â 440 easy, 317 medium, 102 hard â so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit. This chapter covers 6 topics, giving you comprehensive coverage of the entire chapter.