UPSC Prelims 2003 Q26: Science & Technology – Physics
Consider the following statements: A four - wheel vehicle moving on a sharp circular path at
high speed will
1. Overturn about its outer wheels.
2. Overturn about its inner wheels.
3. Skid outwards.
4. Skid inwards.
Which of these statements are correct?
- (a) 1 and 3
- (b) 2 and 4
- (c) 2 and 3
- (d) 1 and 4
Answer: (a) 1 and 3
Explanation
A vehicle on a sharp circular path at high speed
| Statement | Verdict |
|---|---|
| 1. Overturns about its outer wheels | True — the centrifugal effect tilts it outwards |
| 2. Overturns about its inner wheels | False |
| 3. Skids outwards | True — friction cannot supply the needed centripetal force |
| 4. Skids inwards | False |
At high speed on a sharp curve the vehicle tends to overturn about the outer wheels and skid outwards, so statements 1 and 3 are correct.
Answer: (a) 1 and 3.
Why each option is right or wrong
- (a) CORRECT. The vehicle overturns outwards and skids outwards.
- (b) Incorrect. It does not overturn about the inner wheels or skid inwards.
- (c) Incorrect. Overturning about the inner wheels is false.
- (d) Incorrect. Skidding inwards is false.
Key point
Centripetal force v^2/r is supplied by friction; if friction is insufficient, the vehicle skids outwards.
Remember
A fast vehicle on a sharp curve skids and overturns outwards.
Common mistakes
- Thinking the vehicle moves inwards because of the centre of the curve.
- Mixing up overturning with skidding in the answer.
- Forgetting that banking of roads reduces both.
Exam tip
Outward tendency: overturn about the outer wheels and skid outwards.
Sources
- NCERT Class XI Physics — Laws of Motion
- H. C. Verma — Concepts of Physics, Volume 1 (Circular Motion)