Question

A thousand kg car with a speed of 20 m/s is brought to rest in a distance of 50 m.Find the acceleration is the car? Also calculate the force acting on it

Answer 1

1)We know that
   Vehical Mass = 1000 kg

Initial Velocity (that is speed) let it be u = 20 ms-1

Final Velocity let it be v= 0ms-1

Distance travelled = 50 m

let the acceleration be "a"


From equation v^2 = u^2 + 2as

putting all value

(0m/s)^2 = (20m/s)^2 + 2*(a)*50 m

0m2/s^2 = 400m2/s^2 + 100(a) m

0m2/s^2 - 400m2/s^2 = 100(a) m     (Side changing)

-400m2/s^2 = 100(a) meter

-400m2/s^2 / 100 m =(a )        (side changing and cancelling m with m2)

-4m/s^2 = a

a = -4 m/s^2

2)a= -4 m/s^2 

F = ma ⇒
F = 1,000 × -4 = -4,000

Note:  Negative symbol represents The opposit direction to the displacement.