Question

2. A motorcycle rider moving with initial velocity of 15.0 m/s uniformly accelerates to a speed of 30.0 m/s in a.

Answer 1

Given :

Initial velocity , u = 15 m/s .

Final velocity , v = 30 m/s .

Distance travelled , d = 40 m .

Also , this body is uniformly accelerating .

To Find :

(a) What is the acceleration .

(b) How long does this take .

Solution :

Let , acceleration be a .

By , equation of motion :

$v^2-u^2=2ad\\\\a=\dfrac{v^2-u^2}{2d}\\\\a=\dfrac{30^2-15^2}{2\times 40}\\\\a=8.44\ m/s^2$

Also , by equation :

$v=u+at\\\\t=\dfrac{v-u}{a}\\\\t=\dfrac{30-15}{8.44}\ s\\\\t=1.78\ s$

Hence , this is the required solution .