8.The velocity of a particle moving with a uniform acceleration of 10m/s2 after 5s is 50m/s. Its velocity at t= 4s is

solution:

In the above problem, acceleration of a particle is (a)=10m/s2

time=5s

final velocity=50m/s

but it is moving with uniform acceleration.

v=u+at

50=u+10*5

u=0m/s i.e it starts with zero initial vvelocity

then we have to calculate velocity at 4s

for this

a=4m/s2

t=4s

u=0m/s

v=0+10*4

v=40m/s

the velocity at 4s is 40m/s.