Question

What is the final velocity of a bus if it starts from rest having acceleration of 0.8m/s2 until the distance of 1km ? How much time does it take to cover 1km?

Answer 1

let v be final velocity ,that we have to find
u be initial velocity,which is 0
acceleration(a)=0.8m/s^2,distance(s)=1 km=1000 m
Now,we use third law of motion because time is not there
v^2-u^2=2as
v^2-0=2*0.8*1000
v^2=1600
v=40 m/s
so we got the v
now putting the value in first law of motion
v=u+at
40=0+0.8t
40=0.8t
t=50 seconds