Question

A scooter starting from rest moves with constant acceleration for time $\Delta t_1$ , then with a constant velocity for time $\Delta t_2$ and finally with constant deceleration for time $\Delta t_3$ to come to rest. A man of weight of $600\text{N}$ sitting behind the driver manages to be at rest with respect to the scooter without touching any other part. The force exerted by the seat on the man is

• A. $600\text{N}$ throughout the journey.
• B. less than $600\text{N}$ throughout the journey.
• C. more than $600\text{N}$ throughout the journey.
• D. $>600\text{N}$ for a times $\Delta t_1$ and $\Delta t_3$ and $=600\text{N}$ for $\Delta t_2$

Answer 1

The correct option is D $>600\text{N}$ for a times $\Delta t_1$ and $\Delta t_3$ and $=600\text{N}$ for $\Delta t_2$

During the constant velocity time $\left(\Delta t_2\right)$ there will be no reltaive motion between the man and the seat and during that interval the only force acting will be the weight of the man $\text{600 N}$,

during the motion of inteval $\left(\Delta t_1\right)$ and $\left(\Delta t_3\right)$ the seat will exert an additional frictional force on man in horizontal direction let say $f$ so the net force will become $\sqrt{{\text{600}}^2+f^2}>600$

Hence option d will be the answer