Question

A car is moving with speed 54km/h. It stop in 5m after applying the breaks. find the force on the car by the road. If mass of the car is 200kg.​

Answer 1

Explanation:

$speed \:of \: car \: = 54 \: km/h \\ = \frac{54 \times 1000}{60 \times 60} \\ = \frac{540}{36} \\ = 15 m/s \\ time \: = \: 5 \: m = 5 \times 60 = 300 \: s \\ now\\ force \: applied \: on \: car \: by \: road \\ = acceleration \times mass \\ = \frac{15}{300} \times 200 \\ = \frac{15 \times 200}{300} \\ = \frac{3000}{300} \\ 10 \: N$

Thus, the force applied by road on the car is 10 Newton.

Answer 2

u=54km/hr

convert km/h into ms-1

=54×5/18

=15ms-1

T = 5m

v =0

F=?

Mass=200kg

Using this formula:

a = v-u/t

a= 0-15/5

a= 3 ms-1

F = ma

F = 200 × 3

F = 600N