Q. A 10 kg object is dropped from a height of 20 m. What is its potential energy at the top? (2020)
A.
200 J
B.
1000 J
C.
1500 J
D.
3000 J
Show solution
Solution
Potential Energy = mass × g × height = 10 kg × 10 m/s² × 20 m = 2000 J
Correct Answer:
B
— 1000 J
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Q. A 10 kg object is dropped from a height of 20 m. What is its potential energy at the top? (g = 9.8 m/s²) (1960)
A.
196 J
B.
98 J
C.
294 J
D.
490 J
Show solution
Solution
Potential Energy (PE) = mgh = 10 kg × 9.8 m/s² × 20 m = 1960 J.
Correct Answer:
C
— 294 J
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Q. A 10 kg object is dropped from a height of 20 m. What is the potential energy at the top? (2022)
A.
200 J
B.
1000 J
C.
500 J
D.
400 J
Show solution
Solution
Potential Energy = mass × g × height = 10 kg × 9.8 m/s² × 20 m = 1960 J
Correct Answer:
B
— 1000 J
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Q. A 10 kg object is lifted to a height of 2 m. What is the work done against gravity? (g = 9.8 m/s²)
A.
196 J
B.
98 J
C.
20 J
D.
39.2 J
Show solution
Solution
Work done (W) = m × g × h = 10 kg × 9.8 m/s² × 2 m = 196 J.
Correct Answer:
A
— 196 J
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Q. A 10 kg object is moving with a velocity of 4 m/s. What is its kinetic energy?
A.
80 J
B.
40 J
C.
20 J
D.
160 J
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Solution
Kinetic Energy = 0.5 × mass × velocity² = 0.5 × 10 kg × (4 m/s)² = 80 J
Correct Answer:
A
— 80 J
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Q. A 10 kg object is thrown upwards with a velocity of 15 m/s. What is the maximum height it reaches? (g = 9.8 m/s²)
A.
11.5 m
B.
22.5 m
C.
15.0 m
D.
7.5 m
Show solution
Solution
Using energy conservation: KE_initial = PE_max; 0.5 * m * v² = mgh; h = v² / (2g) = (15 m/s)² / (2 * 9.8 m/s²) = 11.5 m.
Correct Answer:
A
— 11.5 m
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Q. A 10 N force is applied at an angle of 60° to the horizontal while moving an object 4 m. What is the work done?
A.
20 J
B.
40 J
C.
30 J
D.
10 J
Show solution
Solution
Work done (W) = F × d × cos(θ) = 10 N × 4 m × cos(60°) = 10 × 4 × 0.5 = 20 J.
Correct Answer:
C
— 30 J
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Q. A 10 N force is applied to move an object 3 m. What is the work done if the force is applied at an angle of 60 degrees to the direction of motion?
A.
15 J
B.
30 J
C.
25 J
D.
20 J
Show solution
Solution
Work done = Force × Distance × cos(θ) = 10 N × 3 m × cos(60°) = 10 N × 3 m × 0.5 = 15 J
Correct Answer:
A
— 15 J
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Q. A 1000 kg car is moving at a speed of 15 m/s. What is its kinetic energy?
A.
112,500 J
B.
75,000 J
C.
50,000 J
D.
25,000 J
Show solution
Solution
Kinetic Energy = 0.5 * m * v² = 0.5 * 1000 kg * (15 m/s)² = 112,500 J.
Correct Answer:
A
— 112,500 J
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Q. A 1000 kg car is moving at a speed of 36 km/h. What is its kinetic energy? (1 km/h = 1/3.6 m/s) (2000)
A.
500 J
B.
1000 J
C.
2000 J
D.
5000 J
Show solution
Solution
First convert speed: 36 km/h = 10 m/s. KE = 0.5 × m × v² = 0.5 × 1000 kg × (10 m/s)² = 0.5 × 1000 × 100 = 50000 J.
Correct Answer:
C
— 2000 J
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Q. A 1000 W electric motor runs for 2 hours. How much work does it do? (2023)
A.
720,000 J
B.
1,000,000 J
C.
2,000,000 J
D.
1,440,000 J
Show solution
Solution
Work = Power × Time = 1000 W × (2 × 3600 s) = 7,200,000 J.
Correct Answer:
D
— 1,440,000 J
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Q. A 15 kg object is lifted to a height of 4 m. What is the work done against gravity? (g = 9.8 m/s²) (2021)
A.
588 J
B.
5880 J
C.
392 J
D.
294 J
Show solution
Solution
Work = mgh = 15 kg * 9.8 m/s² * 4 m = 588 J.
Correct Answer:
A
— 588 J
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Q. A 15 kg object is moving at a speed of 4 m/s. What is its kinetic energy?
A.
120 J
B.
240 J
C.
480 J
D.
60 J
Show solution
Solution
Kinetic Energy (KE) = 0.5 × m × v² = 0.5 × 15 kg × (4 m/s)² = 0.5 × 15 × 16 = 120 J.
Correct Answer:
B
— 240 J
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Q. A 1500 kg car accelerates from rest to a speed of 25 m/s. What is the work done on the car?
A.
468,750 J
B.
375,000 J
C.
250,000 J
D.
187,500 J
Show solution
Solution
Work done = Change in Kinetic Energy = 0.5 * m * v² = 0.5 * 1500 kg * (25 m/s)² = 468,750 J.
Correct Answer:
A
— 468,750 J
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Q. A 1500 kg car is moving at a speed of 25 m/s. What is its kinetic energy? (2021)
A.
468,750 J
B.
1,875,000 J
C.
937,500 J
D.
750,000 J
Show solution
Solution
Kinetic Energy = 0.5 × mass × velocity² = 0.5 × 1500 kg × (25 m/s)² = 468,750 J
Correct Answer:
B
— 1,875,000 J
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Q. A 2 kg object is lifted to a height of 5 m. What is the potential energy gained by the object? (2022)
A.
10 J
B.
20 J
C.
30 J
D.
40 J
Show solution
Solution
Potential Energy = mass × g × height = 2 kg × 10 m/s² × 5 m = 100 J
Correct Answer:
B
— 20 J
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Q. A 2 kg object is lifted to a height of 5 m. What is the potential energy gained by the object? (g = 9.8 m/s²)
A.
98 J
B.
19.6 J
C.
39.2 J
D.
49 J
Show solution
Solution
Potential Energy = mass × g × height = 2 kg × 9.8 m/s² × 5 m = 98 J
Correct Answer:
A
— 98 J
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Q. A 2 kg object is pushed with a force of 10 N over a distance of 5 m. What is the work done on the object?
A.
25 J
B.
50 J
C.
75 J
D.
100 J
Show solution
Solution
Work done = Force * Distance = 10 N * 5 m = 50 J.
Correct Answer:
B
— 50 J
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Q. A 3 kg object is dropped from a height of 10 m. What is its potential energy at the top? (g = 9.8 m/s²)
A.
294 J
B.
30 J
C.
39.2 J
D.
19.6 J
Show solution
Solution
Potential Energy (PE) = m × g × h = 3 kg × 9.8 m/s² × 10 m = 294 J.
Correct Answer:
A
— 294 J
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Q. A 3 kg object is dropped from a height of 10 m. What is the potential energy at the top? (2022)
A.
30 J
B.
60 J
C.
90 J
D.
120 J
Show solution
Solution
Potential Energy = mass × g × height = 3 kg × 10 m/s² × 10 m = 300 J
Correct Answer:
C
— 90 J
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Q. A 3 kg object is dropped from a height of 5 m. What is the potential energy at the top? (g = 9.8 m/s²)
A.
14.7 J
B.
29.4 J
C.
39.2 J
D.
49.05 J
Show solution
Solution
PE = mgh = 3 kg × 9.8 m/s² × 5 m = 147 J.
Correct Answer:
C
— 39.2 J
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Q. A 3 kg object is lifted to a height of 4 m. What is the work done against gravity? (g = 9.8 m/s²)
A.
117.6 J
B.
29.4 J
C.
39.2 J
D.
78.4 J
Show solution
Solution
Work done (W) = mgh = 3 kg × 9.8 m/s² × 4 m = 117.6 J.
Correct Answer:
A
— 117.6 J
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Q. A 3 kg object is pushed with a force of 12 N over a distance of 4 m. What is the work done on the object?
A.
24 J
B.
36 J
C.
48 J
D.
60 J
Show solution
Solution
Work done (W) = Force (F) × Distance (d) = 12 N × 4 m = 48 J.
Correct Answer:
C
— 48 J
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Q. A 4 kg object is lifted to a height of 2 m. What is the work done against gravity? (2022)
A.
40 J
B.
80 J
C.
20 J
D.
60 J
Show solution
Solution
Work done = mass × g × height = 4 kg × 10 m/s² × 2 m = 80 J
Correct Answer:
B
— 80 J
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Q. A 4 kg object is lifted to a height of 5 m. What is the work done against gravity? (g = 9.8 m/s²)
A.
19.6 J
B.
39.2 J
C.
49 J
D.
196 J
Show solution
Solution
Work done against gravity = mgh = 4 kg × 9.8 m/s² × 5 m = 196 J.
Correct Answer:
B
— 39.2 J
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Q. A 5 kg object is dropped from a height of 10 m. What is its potential energy at the top? (g = 9.8 m/s²)
A.
490 J
B.
98 J
C.
50 J
D.
100 J
Show solution
Solution
Potential Energy = mgh = 5 kg * 9.8 m/s² * 10 m = 490 J.
Correct Answer:
A
— 490 J
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Q. A 5 kg object is dropped from a height of 10 m. What is its speed just before it hits the ground? (g = 9.8 m/s²)
A.
14 m/s
B.
20 m/s
C.
10 m/s
D.
15 m/s
Show solution
Solution
Using energy conservation, Potential Energy = Kinetic Energy at the ground: mgh = 0.5mv²; v = √(2gh) = √(2 × 9.8 m/s² × 10 m) = 14 m/s
Correct Answer:
A
— 14 m/s
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Q. A 50 kg object is moving with a velocity of 4 m/s. What is its kinetic energy?
A.
100 J
B.
200 J
C.
400 J
D.
800 J
Show solution
Solution
Kinetic Energy (KE) = 0.5 * m * v² = 0.5 * 50 kg * (4 m/s)² = 400 J.
Correct Answer:
C
— 400 J
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Q. A block of mass 2 kg is lifted to a height of 5 m. What is the work done against gravity? (g = 9.8 m/s²)
A.
98 J
B.
196 J
C.
49 J
D.
20 J
Show solution
Solution
Work done = mgh = 2 kg * 9.8 m/s² * 5 m = 98 J.
Correct Answer:
B
— 196 J
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Q. A car accelerates from rest to a speed of 20 m/s. If its mass is 1000 kg, what is the kinetic energy of the car at this speed? (2000)
A.
200 J
B.
1000 J
C.
2000 J
D.
4000 J
Show solution
Solution
Kinetic Energy (KE) = 0.5 × m × v² = 0.5 × 1000 kg × (20 m/s)² = 0.5 × 1000 × 400 = 200000 J.
Correct Answer:
C
— 2000 J
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Showing 1 to 30 of 103 (4 Pages)
Work, Energy & Power MCQ & Objective Questions
Understanding the concepts of Work, Energy, and Power is crucial for students preparing for school and competitive exams. These topics not only form the foundation of physics but also frequently appear in various examination formats. Practicing MCQs and objective questions helps students enhance their problem-solving skills and boosts their confidence, ultimately leading to better scores in exams.
What You Will Practise Here
Definition and units of Work, Energy, and Power
Work done by a constant force and variable force
Kinetic and potential energy concepts and formulas
Law of conservation of energy
Power calculations and its significance in real-life scenarios
Work-Energy theorem and its applications
Diagrams illustrating energy transformations
Exam Relevance
The topics of Work, Energy, and Power are integral to the physics syllabus across various boards, including CBSE and State Boards. In competitive exams like NEET and JEE, these concepts are often tested through numerical problems and conceptual questions. Common patterns include direct application of formulas, conceptual understanding of energy conservation, and problem-solving involving real-world scenarios. Familiarity with these areas can significantly enhance your performance in exams.
Common Mistakes Students Make
Confusing work done with energy transferred
Misapplying the work-energy theorem in different contexts
Overlooking the direction of force when calculating work
Neglecting units while solving numerical problems
Failing to differentiate between kinetic and potential energy in questions
FAQs
Question: What is the formula for calculating work done?Answer: Work done is calculated using the formula W = F × d × cos(θ), where W is work, F is the force applied, d is the distance moved, and θ is the angle between the force and the direction of motion.
Question: How is power defined in physics?Answer: Power is defined as the rate at which work is done or energy is transferred, calculated using the formula P = W/t, where P is power, W is work done, and t is the time taken.
Now is the time to strengthen your understanding of Work, Energy, and Power! Dive into our practice MCQs and test your knowledge to excel in your exams. Remember, practice makes perfect!
