A cyclist leans inward while taking a turn because:
- A.It reduces the weight of the cycle
- B.The reaction of the ground then has a horizontal component towards the centre of the turn
- C.It increases the rolling friction of the tyres
- D.It makes the centrifugal force disappear
Correct answer
Explanation
The correct answer is B. To move along a curve a body needs a force directed towards the centre of that curve. When the cyclist leans inward, the reaction of the ground on the tyres is no longer vertical: its vertical component still balances the weight while its horizontal component points to the centre of the turn and supplies the centripetal force, so the turn can be taken at a higher speed than friction alone would allow. Option A is wrong because leaning changes no mass and no weight. Option C is wrong because the friction available depends on the surfaces and the normal reaction, not on the lean, and more rolling friction would in any case slow the cycle rather than turn it. Option D misstates the idea: the centrifugal force is only a pseudo force seen from the rotating frame and it cannot be made to disappear by leaning. The banking of roads and the raised outer rail of a curved track work on the same principle.
Read the full article: Friction and Circular Motion: Laws, Formulas and PYQs
Practice Questions
View allWhen a force resists the relative motion between two surfaces, it is called _______
- A.Resistance
- B.Convection
- C.Friction
- D.Induction
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Friction is defined as the force that opposes the relative motion, or the tendency of relative motion, between two surfaces in contact; it acts along the surfaces and always against the direction of motion.
Read the full explanation →Which of the following statements about the coefficient of friction is correct?
- A.It is measured in newton
- B.It has no unit and no dimensions
- C.It is measured in newton per square metre
- D.It is measured in joule
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The coefficient of friction is the ratio of the limiting or kinetic frictional force to the normal reaction, and since both are forces the ratio is a pure number; the same reasoning applies to other ratios such as the refractive index and relative density.
Read the full explanation →For the same pair of surfaces, which of the following types of friction is the smallest?
- A.Static friction
- B.Limiting friction
- C.Sliding friction
- D.Rolling friction
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When a body rolls, the surfaces in contact change continuously and the irregularities have no time to interlock deeply, so rolling friction is very much smaller than sliding friction; this single fact is the reason the wheel was invented and the reason a ball bearing is fitted wherever a shaft…
Read the full explanation →In uniform circular motion, which of the following quantities remains constant?
- A.Velocity
- B.Speed
- C.Acceleration
- D.Linear momentum
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In uniform circular motion the body covers equal arcs in equal times, so its speed, a scalar, does not change; its kinetic energy and its angular velocity are constant too.
Read the full explanation →A body of mass 5 kg is rotating with angular velocity 10 rad/s in a circular path of radius 0.1 m. Determine the centrifugal force acting on the body.
- A.100 N
- B.50 N
- C.80 N
- D.60 N
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The centrifugal force has the same magnitude as the centripetal force, which for a body moving in a circle is the mass multiplied by the square of the angular velocity multiplied by the radius.
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