Motion on Flat Circular Tracks & Friction — NEET Physics MCQs with Solutions
Free NEET Physics Motion on Flat Circular Tracks & Friction MCQs with step-by-step solutions (8 questions). Part of Circular Motion. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Motion on Flat Circular Tracks & Friction · easy · theory
On a flat (unbanked) road, the centripetal force for a turning car is provided by:
A. Static friction between the tyres and the road ✓ Correct
B. The car's weight
C. The normal reaction
D. The engine thrust directly
Solution: Friction is the only horizontal force available on level ground; v_max = √(μrg).
Q2 — Motion on Flat Circular Tracks & Friction · medium · theory
The maximum safe speed on a flat circular road is independent of:
A. The mass of the vehicle ✓ Correct
B. The coefficient of friction
C. The radius of the turn
D. The value of g
Solution: μmg = mv²/r ⇒ v_max = √(μrg) — mass cancels. Trap: heavier cars can NOT corner faster on this account.
Q3 — Motion on Flat Circular Tracks & Friction · easy · numerical
A car turns on a flat road of radius 45 m with μ = 0.5. The maximum safe speed is:
A. 15 m/s ✓ Correct
B. 22.5 m/s
C. 9 m/s
D. 30 m/s
Solution: v = √(μrg) = √(0.5×45×10) = √225 = 15 m/s.
Q4 — Motion on Flat Circular Tracks & Friction · medium · numerical
A coin sits 0.2 m from the centre of a turntable (μ = 0.5). The maximum angular speed before it slips is:
A. 5 rad/s ✓ Correct
B. 10 rad/s
C. 25 rad/s
D. 2.5 rad/s
Solution: μg = ω²r ⇒ ω = √(μg/r) = √(0.5×10/0.2) = √25 = 5 rad/s.
Q5 — Motion on Flat Circular Tracks & Friction · hard · numerical
A car circles a flat track at the maximum safe speed for radius r. To take a turn of radius r/4 on the same surface, its maximum speed must be:
A. Unchanged
B. Twice the original
C. Half the original ✓ Correct
D. A quarter of the original
Solution: v_max ∝ √r ⇒ √(1/4) = 1/2 — tighter turns demand much lower speeds.
Q6 — Motion on Flat Circular Tracks & Friction · medium · numerical
A cyclist at 10 m/s brakes while turning on a flat road of radius 20 m (μ = 0.5, g = 10). The friction needed just for the turn (per kg) is:
A. 10 m/s²
B. 2.5 m/s²
C. 5 m/s² — exactly the friction limit, so no braking margin remains ✓ Correct
D. 1 m/s²
Solution: a_c = v²/r = 100/20 = 5 m/s² = μg — friction is fully used by the turn; any braking causes a skid. This is why you slow BEFORE a corner.
Q7 — Motion on Flat Circular Tracks & Friction · easy · numerical
With μ = 0.8 between tyres and road, the maximum speed on a level turn of radius 20 m is:
A. ≈ 16 m/s
B. ≈ 4 m/s
C. ≈ 12.6 m/s ✓ Correct
D. ≈ 8 m/s
Solution: v = √(μrg) = √(0.8×20×10) = √160 ≈ 12.6 m/s.
Q8 — Motion on Flat Circular Tracks & Friction · medium · numerical
A vehicle takes a flat turn of radius 30 m at 12 m/s. The minimum coefficient of friction required is:
A. 0.4
B. 0.24
C. 0.6
D. 0.48 ✓ Correct
Solution: μ_min = v²/rg = 144/300 = 0.48.