ECAT Physics — Circular Motion
Circular Motion is part of the Physics section of the UET ECAT (30 of the 100 MCQs). It breaks into 3 subtopics, and we hold 32 ECAT-pattern practice MCQs on it, each with a written explanation. Tap a subtopic below to practise just that.
Subtopics (3)
How Circular Motion is tested
Across the 7 ECAT past papers on ParhaiKrlo, Circular Motion accounts for 10 questions. It appears in 6 of them, about 1.7 questions a paper. The heaviest was ECAT Past Paper 01, with 3 questions, and the most recent is ECAT Past Paper 06, with 1.
| Paper | Questions |
|---|---|
| ECAT Past Paper 06 | 1 |
| ECAT Past Paper 05 | 1 |
| ECAT Past Paper 04 | 1 |
| ECAT Past Paper 03 | 2 |
| ECAT Past Paper 02 | 2 |
| ECAT Past Paper 01 | 3 |
Circular Motion MCQs from the ECAT past papers
Try each one before opening the answer. Each comes with a short explanation.
- Q1 · ECAT Past Paper 06 · Circular Motion
Two satellites are to be launched from the Earth's surface. Satellite 1 has mass 10 kg and volume 1500 cm³; satellite 2 has mass 5 kg and volume 1000 cm³. Their escape velocities v₁ and v₂ are related by:
- A.Relation depends on the launch
- B.v₁ = v₂
- C.v₁ > v₂
- D.v₁ < v₂
Show answer
Answer: B. v₁ = v₂ — Escape velocity √(2GM/R) depends only on the planet, not on the mass or size of the object.
- Q2 · ECAT Past Paper 05 · Circular Motion
Which of the following remains constant if no torque acts upon a body?
- A.Linear momentum
- B.Angular momentum
- C.Momentum
- D.Charge
Show answer
Answer: B. Angular momentum — τ = dL/dt; with zero torque, angular momentum is conserved.
- Q3 · ECAT Past Paper 04 · Circular Motion
A 100 kg satellite 400 km above the Earth has an orbital speed of v. A 200 kg satellite in the same orbit will require an orbital speed of:
- A.v
- B.2v
- C.v√2
- D.√(2v)
Show answer
Answer: A. v — Orbital speed v = √(GM/r) does not depend on the satellite's mass.