Question

a 2000 kg car travelling at 20 m/s comes to rest on a level ground in a distance of 100 m. how large is the average frictional froce tending to stop it​

Answer 1

Answer: The average frictional force is 4000 N.

Explanation:

Given that,

Mass of car = 2000 kg

initial velocity u = 20 m/s

Final velocity v = 0

Distance d = 100 m

Using equation of motion

$v^{2} =u^{2} + 2as$

$0 = (200m/s)^{2} + 2\times a\times 100m$

$a = -2 m/s^{2}$

Negative sign shows of retardation

Now, using newton's law

$F = ma$

$F = 2000 kg \times-2\ m/s^{2}$

$F = -4000 N$

Hence, the average frictional force is 4000 N.