Question

A bus accelerates uniformly from $54km/hr$ to $72km/hr$ in $10s$. Calculate the distance covered by the bus in metres during interval and also find the acceleration in metre per second square.

Answer 1

Step 1: Given

Initial velocity, $u=54km/hr=15m/s$

Final velocity, $v=72km/hr=20m/s$

Time, $t=10s$

Step 2: Calculate the acceleration

Using first equation of motion,

$$\begin{gathered} a=\frac{v-u}{t} \\ =\frac{20-15}{10} \\ =0.5m/s^2 \end{gathered}$$

Step 3: Calculate the distance traveled by bus

Using the third equation of motion, the distance $s$ can be calculated

$$\begin{gathered} v^2=u^2+2as \\ {20}^2={15}^2+2(0.5)s \\ s=\frac{{20}^2-{15}^2}{2(0.5)} \\ s=175m \end{gathered}$$

Therefore, the distance covered is $175m$ and the acceleration is $0.5m/s^2$