Work Done By A Force At Right Angles
A satellite moves in a perfectly circular orbit around the Earth under the gravitational pull directed toward the centre. How much work does the gravitational force do on the satellite during one complete revolution?
Select the correct option:
🔒 Solution Hidden from View
Submit your answer to unlock the detailed step-by-step solution.
More work, energy and power Practice Questions
A rubber ball is dropped from a height of 2 m onto a hard floor and rebounds to a height of 1.28 m a...
A rubber ball is dropped from a height of 2 m onto a hard floor and rebounds to a height of 1.28 m a...
A cyclist of total mass 70 kg rides up a slope inclined at 30 degrees to the horizontal at a steady ...
A cyclist of total mass 70 kg rides up a slope inclined at 30 degrees to the horizontal at a steady ...
A stone of mass 0.5 kg is dropped from rest at a height of 8 m above the ground. Ignoring air resist...
A stone of mass 0.5 kg is dropped from rest at a height of 8 m above the ground. Ignoring air resist...
Two bodies of different masses possess the same magnitude of linear momentum while moving in a strai...
Two bodies of different masses possess the same magnitude of linear momentum while moving in a strai...
A small stone tied to a string is whirled in a vertical circle of radius 2 m. What is the minimum sp...
A small stone tied to a string is whirled in a vertical circle of radius 2 m. What is the minimum sp...
A weightlifter raises a barbell of mass 80 kg from the floor to a height of 2 m above the floor in 4...
A weightlifter raises a barbell of mass 80 kg from the floor to a height of 2 m above the floor in 4...
A ball is thrown vertically upward and returns to the same height from which it was launched on a wi...
A ball is thrown vertically upward and returns to the same height from which it was launched on a wi...
A car engine delivers a constant power of 50 kW while the car moves at a steady speed of 25 m/s alon...
A car engine delivers a constant power of 50 kW while the car moves at a steady speed of 25 m/s alon...
A 2 kg lump of clay moving at 6 m/s strikes and sticks to a 4 kg block initially at rest on a fricti...
A 2 kg lump of clay moving at 6 m/s strikes and sticks to a 4 kg block initially at rest on a fricti...
A wooden crate of mass 10 kg is dragged 5 m up a rough incline by a force, and friction exerts a con...
A wooden crate of mass 10 kg is dragged 5 m up a rough incline by a force, and friction exerts a con...
Which of the following statements correctly distinguishes a conservative force from a non-conservati...
Which of the following statements correctly distinguishes a conservative force from a non-conservati...
A spring with force constant 400 N/m is compressed by 0.1 m and used to launch a small block on a fr...
A spring with force constant 400 N/m is compressed by 0.1 m and used to launch a small block on a fr...
About This Question
- Subject
- physics
- Chapter
- work, energy and power
- Topic
- work done by a force at right angles
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
Zero
As explained in NCERT Class 11, Chapter 6 (Work, Energy and Power), the work done by a force is W = F·d·cos(theta), and it vanishes whenever the force is perpendicular to the displacement. In a circular orbit the gravitational force always points toward the centre, while the satellite's velocity and hence its instantaneous displacement are always tangential, so the angle between them is 90 degrees and cos(90) = 0 at every instant. Therefore gravity does zero work throughout, and the satellite's speed and kinetic energy stay constant. The option about positive work equal to kinetic energy contradicts the constancy of speed. The option about negative work mislabels the situation. The option involving speed times circumference ignores the perpendicularity. A consistency check: since the orbital speed is constant, the work-energy theorem demands zero net work, fully agreeing with the geometric argument.
This medium difficulty physics question is from the chapter work, energy and power, covering the topic of work done by a force at right angles. It appeared in the 2025 exam.
Looking for more practice? Explore all physics questions or browse work, energy and power questions on RankGuru.