Question

What average force is required to stop a 950-kg car in 8.0 s if the car is traveling at 95 km/h?

Answer 1

Hello there,

1 km/hr = 5/18 m/s

Hence, 95 km/hr is converted to m/s

⇒ 95 × 5/18 m/s = 26.4 m/s

Since finally by applying force we will bring it to velocity of 0 m/s.

⇒v = u + at

⇒0 = 26.4 + a(8)

⇒- 26.4/8 = a

⇒- 3.3 m/s² = a

So, Force = ma

⇒F = 950 kg × ( - 3.3 m/s² )

⇒F = - 3,135 N

Here negative sign shows that force will be applied against direction of motion.

Hope you find my answer useful.

Harith