Question

An object moving with velocity of 15m/s accelerate at 2m/s for 5sec.
Calculate the final velocity and the distance traveled?

Answer 1

Answer

Initial velocity = 15 m/s

Acceleration = 2 m/s^2

Time = 5 sec

Using the kinematic equation

S = ut + 1/2 at^2

S = (15 m/s x 5s) + 1/2 x (2m/s^2) x (5s)^2

S = 75m + 1/2 x (2m/s^2) x 25s^2

S = 75 m + 1/2 x 50 m

S = 75 m + 25m

S = 100m

Next kinematic equation to find final velocity

v^2 - u^2 = 2aS

v^2 - (15m/s)^2 = 2 x (2m/s^2) x 100m

v^2 - 225 m^2/s^2 = 2 x (200m^2/s^2)

v^2 - 225 m^2/s^2 = 400m^2/s^2

v^2  = 400 m^/s^2 + 225 m^2/s^2

v^2  = 625 m^2/s^2

v      = $\sqrt{625 m^2/s^2$

v      = 25 m/s  

HOPE IT HELPS . Write it on a piece of paper to avoid confusion . You will also understand the unit cancellation .