Question

A car running at a speed of 72 km/h is to be stopped in exactly 10 seconds. Find the uniform deceleration needed.

Answer 1

Given quantities:

$v_o = 72 \frac{km}{h}=20 \frac{m}{s}$

$v = 0$

$t = 10s$

$a - ?$

$a = \large\frac{v-v_o}{t}=-2\frac{m}{s^2}$

the uniform deceleration is $-2\frac{m}{s^2}$