Question

A RACE CAR HAS A MASS OF 710 KG. IT STARTS FROM REST AND TRAVELS 40 M IN 3 S. THE CAR IS UNIFORMLY ACCELERATED DURING THE ENTIRE TIME. WHAT NET FORCE IS APPLIED TO IT ?

Answer 1

Given:

$m=710\:\rm kg$

$v_0=0$

$d=40\:\rm m$

$t=3\:\rm s$

The distance traveled by a car

$$d=v_0t+at^2/2=at^2/2$$

Hence, the acceleration of the car

$$a=\frac{2d}{t^2}=\frac{2*40}{3^2}=8.89\:\rm m/s^2$$

The Newton's second law says

$$F=ma=710*8.89=6311\:\rm N$$