A 2600 kg car traveling to the north is slowed down uniforml

A 2600 kg car traveling to the north is slowed down uniformly from an initial velocity of 30.5 m/s by a 7670 N braking force acting opposite the car\'s motion. What is the car\'s velocity after 1.87 s? Answer in units of m/s.

Solution

Now the body inititally is moving at 30.5m/s and then brakes are applied. So, the total force acting in the horizontal frame is only the frictional force of the brakes and it results in decelaration of the car, hence,

F = M x a

-7670 = 2600 x a ( -ve since opposite direction of its motion )

a = -2.95 m/s/s

Now we can apply kinematic equation to get velocity after 1.87 seconds

v = u + ( a x t)

= 30.5 - 2.95x1.87

Final velocity v = 24.97 m/s