Question

a body starts from rest and is found to cover 3 M during the fifth second of its motion find the acceleration if it is uniformly accelerated

Answer 1

Given conditions ⇒

A body is starts at the rest,
∴ Initial Velocity of the body (u) = 0

Now, Distance covered b the body = 3 m.
Time taken by the body = 5 seconds.
∴ Velocity of the body = Distance/Time
 = 3/5
 = 0.6 m/s.
∴ Final Velocity (v) of the body = 0.6 m/s.


Now, Using the Formula,
 $Acceleration = \frac{Final Velocity - Initial Velocity}{Time}$
∴ $a = \frac{v - u}{t}$
∴ $a = \frac{0.6 - 0}{5}$
∴ a = 0.12 m/s².


Hence, the acceleration of the body is 0.12 m/s².


Hope it helps.

Answer 2

Answer:

In this case,we know that u=0 and to find a, such that the distance covered in 5th second is 3m, which is S(5)-S(4)

S(5)=0+1/2a(5)^2=12.5a

S(4)=0+1/2a(4)^2=8a

and S(5)-S(4)=3

so,12.5a-8a=3

therefore a=3/4.5=30/45=6/9=0.667m/s^2

=0.67m/s^2