Question

A truck moving with constant acceleration covers the distance between two points $180m$ apart in $6seconds$. Its speed as it passes the second points $45m/s$. Find
(a) its acceleration, and
(b) its speed when it was at the first point.

Answer 1

Let the initial speed is $v_0$

A to B

$u_i=v_0$, $v=45$

$t=6$ , $s=180m$

$v=u+at$

$45=v_0+6a$ ............( 1 )

$s=ut$ + $\frac{1}{2}a{t}^2$

$180=v_0\times 6+\frac{1}{2}\times a\times 36$

$30=v_0+3a$ .................( 2 )

from ( 1 ) & ( 2 ) equation

$a=5m/s^2$

$v_0=15m/s$

so

( i ) its acceleration = $5m/s^2$

( ii ) its initial speed = $15m/s$