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CBSE Class 9  >  Class 9 Test  >  Science New NCERT 2026-27 (New Syllabus)  >  Test: Work, Energy, and Simple Machines - 2 - Class 9 MCQ

Work, Energy, and Simple Machines - 2 - Free MCQ Practice Test with solutions,


MCQ Practice Test & Solutions: Test: Work, Energy, and Simple Machines - 2 (15 Questions)

You can prepare effectively for Class 9 Science Class 9 New NCERT 2026-27 (New Syllabus) with this dedicated MCQ Practice Test (available with solutions) on the important topic of "Test: Work, Energy, and Simple Machines - 2". These 15 questions have been designed by the experts with the latest curriculum of Class 9 2026, to help you master the concept.

Test Highlights:

  • - Format: Multiple Choice Questions (MCQ)
  • - Duration: 15 minutes
  • - Number of Questions: 15

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Test: Work, Energy, and Simple Machines - 2 - Question 1
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Work done on an object appears as a change in:

Detailed Solution: Question 1

Work-Energy Theorem: Work done = Change in energy. Positive work → energy increases. Negative work → energy decreases. Zero work → no change in energy. This is a universal principle applicable even when forces are variable and for systems of objects.

Test: Work, Energy, and Simple Machines - 2 - Question 2
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1 horsepower (hp) equals:

Detailed Solution: Question 2

1 hp = 746 W ≈ 0.746 kW. Originally defined by comparing steam engines to horses. Used for car engines, pumps, motors. The watt (SI unit) is named after James Watt. Don't confuse: watt = unit of power; joule = unit of energy. 1 hp = 746 W is a standard value to memorise.

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Test: Work, Energy, and Simple Machines - 2 - Question 3
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A pump lifts 200 kg of water to 5 m height in 10 s. Its power is: (g = 10 m/s²)

Detailed Solution: Question 3

W = mgh = 200 × 10 × 5 = 10,000 J. P = W/t = 10,000/10 = 1,000 W = 1 kW. In horsepower: 1000/746 ≈ 1.34 hp. If the same work were done in 5 s instead of 10 s, power would be 2,000 W — double — showing that time taken affects power even for identical work.

Test: Work, Energy, and Simple Machines - 2 - Question 4
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Which correctly describes a lever?

Detailed Solution: Question 4

A lever is a rigid bar rotating about the fulcrum. Components: Fulcrum (pivot), Load arm (d₂), Effort arm (d₁). Principle: Effort × d₁ = Load × d₂. Option B describes a pulley. Option C describes an inclined plane. Option D describes a spring (elastic PE storage). Examples of levers: seesaw, scissors, crowbar, bottle opener.

Test: Work, Energy, and Simple Machines - 2 - Question 5
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Effort arm = 60 cm, load arm = 20 cm. What is the mechanical advantage?

Detailed Solution: Question 5

MA = Effort arm / Load arm = 60/20 = 3. Verification: Effort × 60 = Load × 20 → Load/Effort = 3 = MA ✓. A 100 N effort can lift a 300 N load. However, the effort moves 60 cm while the load moves only 20 cm. Work done: 100 × 60 = 300 × 20 = 6000 N·cm. Work is conserved.

Test: Work, Energy, and Simple Machines - 2 - Question 6
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Which form of energy is stored in a compressed spring?

Detailed Solution: Question 6

A compressed spring stores elastic potential energy due to deformation. Work done against the spring's restoring force gets stored in this form. When released, elastic PE → KE of the object pushed. Other examples: stretched rubber band, bent bow, squashed rubber ball. Gravitational PE requires height. Kinetic energy requires motion.

Test: Work, Energy, and Simple Machines - 2 - Question 7
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Law of Conservation of Energy states that energy can be:

Detailed Solution: Question 7

Energy can neither be created nor destroyed — it can only be transformed from one form to another. Total energy of an isolated system is always constant. Example: Hydroelectric plant — PE of water → KE → electrical energy. No energy is lost; only converted. This is a fundamental law of physics with no known exceptions in the universe.

Test: Work, Energy, and Simple Machines - 2 - Question 8
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A 10,000 kg truck moving at 20 m/s is stopped by a 50,000 N braking force. Stopping distance is:

Detailed Solution: Question 8

Initial KE = ½ × 10,000 × (20)² = 2,000,000 J. Work by brakes = −50,000 × d. Work-Energy Theorem: −50,000d = 0 − 2,000,000 → d = 2,000,000/50,000 = 40 m. Stopping distance = 40 m. If speed were doubled (40 m/s), KE would be 4× and stopping distance would be 4× = 160 m — showing danger of high-speed driving.

Test: Work, Energy, and Simple Machines - 2 - Question 9
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At which point is PE completely converted to KE for a freely falling object?

Detailed Solution: Question 9

At ground level h = 0: PE = mgh = 0 and KE = ½mv² = mgh (maximum). At start: PE = mgh, KE = 0. Midway: PE = mgh/2, KE = mgh/2 (each half). Just before ground: PE = 0, KE = mgh — complete conversion. Total ME = mgh is conserved throughout (ignoring air resistance).

Test: Work, Energy, and Simple Machines - 2 - Question 10
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What does a fixed pulley do to applied force?

Detailed Solution: Question 10

A fixed pulley is attached to a fixed support. It only rotates — doesn't move. MA = 1 (effort = load). Its sole function is to change the direction of force. Example: to raise a flag, instead of pushing it up, we pull rope downward — more natural and convenient. A movable pulley provides MA > 1 by actually moving with the load.

Test: Work, Energy, and Simple Machines - 2 - Question 11
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The unit 'watt' is named after:

Detailed Solution: Question 11

Watt (W) is named after James Watt (1736–1819), Scottish inventor who developed an efficient steam engine with rotational motion — key to the Industrial Revolution. He also introduced the concept of horsepower. Important distinction: Joule (J) = unit of energy, named after James Prescott Joule. Newton (N) = unit of force, named after Isaac Newton. Do not mix these up in exams.

Test: Work, Energy, and Simple Machines - 2 - Question 12
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A 25 kg child slides down a frictionless slide of height 3.2 m. Speed at the bottom? (g = 10 m/s²)

Detailed Solution: Question 12

Conservation of energy: mgh = ½mv² → v² = 2gh = 2 × 10 × 3.2 = 64 → v = √64 = 8 m/s. Note: mass cancels out! A 25 kg and a 50 kg child both reach the bottom at 8 m/s on the same frictionless slide. Speed depends only on height, not mass — an important result of energy conservation.

Test: Work, Energy, and Simple Machines - 2 - Question 13
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Energy transformation in an electric bulb is:

Detailed Solution: Question 13

In a bulb, electrical energy passes through tungsten filament (high resistance) → heats to ~2500°C → emits light + heat. Much energy is wasted as heat. LED bulbs are more efficient — less heat, more light. Option B = solar cell (reverse). Option C = bioluminescent organisms/glow sticks. Option D = generator/dynamo.

Test: Work, Energy, and Simple Machines - 2 - Question 14
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Load = 500 N, load arm = 40 cm, effort arm = 200 cm. Effort required is:

Detailed Solution: Question 14

Principle of lever: Effort × effort arm = Load × load arm. Effort × 200 = 500 × 40 = 20,000. Effort = 20,000/200 = 100 N. MA = 500/100 = 5. With a 200 cm effort arm, only 100 N is needed to lift 500 N. Effort arm is 5× the load arm → MA = 5. Work done: 100 × 200 = 500 × 40 = 20,000 N·cm (conserved ✓).

Test: Work, Energy, and Simple Machines - 2 - Question 15
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A car engine of 40,000 W power works for 30 s. Work done is:

Detailed Solution: Question 15

W = P × t = 40,000 × 30 = 1,200,000 J = 1.2 × 10⁶ J = 1200 kJ. Power tells us the rate of doing work. A 40 kW engine does 1,200,000 J in 30 s. If the same engine ran for 60 s, work = 2,400,000 J. Higher power engine does more work in the same time — hence faster acceleration.

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About this Class 9 Practice Test

This test contains 15 MCQs on Work, Energy, and Simple Machines - 2 with detailed solutions for each question. It is part of the Science Class 9 New NCERT 2026-27 (New Syllabus) course on EduRev, designed to align with the current Class 9 syllabus. Each solution explains not just the correct answer but also gives you an understanding of the topic — not just to attempt the question but also help you prepare for the exam with practice.

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