Question

An unloaded bus and a loaded bus are both moving with the same kinetic energy. The mass of the latter is twice that of the former. Brakes are applied to both, so as to exert equal retarding force. If $x _ { 1 }$and $x _ { 2 }$be the distance covered by the two buses respectively before coming to a stop, then

• A. $x _ { 1 } = x _ { 2 }$
• B. $2 x _ { 1 } = x _ { 2 }$
• C. $4 x _ { 1 } = x _ { 2 }$
• D. $8 x _ { 1 } = x _ { 2 }$

Answer 1

Answer: (A)

$x _ { 1 } = x _ { 2 }$

Answer 2

If the vehicle stops by retarding force then the ratio of stopping distance $\frac { x _ { 1 } } { x _ { 2 } } = \frac { E _ { 1 } } { E _ { 2 } }$.

But in the given problem kinetic energy of bus and car are given same i.e. E₁ = E₂. ∴ x₁ = x₂ .