Question

A car intially at rest starts moving with a constant acceleration of 0.5 m/s2 and travels a distance of 25 m. Find its final velocity and the time taken

Answer 1

s=ut+1/2at^2

where s=distance travelled

u=initial velocity

a=acceleration

t=time

ATQ, u=0m/s(as the body starts from rest, thus it's obvious that the initial velocity will be 0),t=20s, a=5m/s^2, s=?

Now put the value in the formula:

s=ut+1/2at^2

s=0(20s)+ 1/2(5m/s^2)(20s)^2

s=0+1/2(5m/s^2)(400s^2)

s=1/2(2000m)

s=1000m

Thus, distance travelled is 1000m

Answer 2

initial velocity=0m/sec
acceleration=0.5m/sec
distance=25m
final velocity=?
using the third equation of motion we have:
v2=u2+2as
x2=02+2*0.5*25
x2=02+25
x=5m/sec

time=v-u/a
=5-0/0.5
=5*1/5*10
=1/10sec
=0.1sec