Question

a car of 20 kg moves with 4m/s
find magnitude of force when the car moves with 1 m/s after travelling 20m
a)4 N
b)6 N
c)7.5 N
d)9.5 N

Answer 1

Explanation:

after travelling 20m with 4m/s speed

it travels 1m/s speed

d=20m

v=4m/s

t=d/v=20/4=5s

so after travelling with 4m/s fir 5s its speed reduces to 1 m/s so acceleration is there

a=v-u/t=1-4/5=-3/5= -0.6m/s^2

F=ma= -0.6×20= -12N