Question

A car is moving with a uniform velocity $30m{s}^{-1}$. It is stopped in $2s$ by applying a force of $1500N$ through its brakes. Calculate: the mass of car and the retardation produced in car.

• A. $300$ $kg$, $15$ $m$ $s^{-2}$
• B. $100$ $kg$, $5$ $m$ $s^{-2}$
• C. $10$ $kg$, $15$ $m$ $s^{-2}$
• D. $100$ $kg$, $15$ $m$ $s^{-2}$

Answer 1

The correct option is D $100$ $kg$, $15$ $m$ $s^{-2}$

As we know that $F=\frac{mv}{t}$
where p = momentum
so $1500=\frac{m\times 30}{2}$
mass $\left(m\right)=100$ kg

also force(F) = mass$\times$acceleration
a $=\frac{1500}{100}=15m/s^2$