Question

A car is moving at a speed of 18km per hour it starts retarding uniformly at 1m per second square and comes to rest find the distance travelled

Answer 1

Given..

u-18km/h=18×5/18=5m/s

a--1m/s square

v-0m/s

t=?

s=?

So..

v=u+at

0=5+(-1)×t

0=5-t

5 seconds=t

now..

s=ut+1/2at square

s=5×5+1/2×(-1)×25

s=25-25/2

s=50-25/2

s=25/2

s=12.5m

Answer 2

Given:
a = -1 m/s^2
u = 18 km/hr = 5 m/s
v= 0 km/hr = 0 m/s
Now,
We use third equation of motion, i.e
s = v^2 - u^2/ 2a
Putting the values in the equation, we get,
s = 0^2- 5^2/ 2 X -1
s = -25/-2
s = 12.5 m