a scooter is moving with a velocity of 20 m/s mass of the scooter and the rider is 180 kg the constant force applied by the brakes is 500 N.
how far does the scooter travel before it comes to rest
Answers
Given,
Velocity = 20 m/s
Mass = 180 kg
Force = 500 N
According to Newton's Second Law of Motion,
F = change in momentum/ change in time
So, F = change in (m×v)/ change in t
Placing the values,
500 N = 180 kg × 20 m/s / t
⇒ 500 N = 360 kg m/s / t
⇒t = 360 kg m/s / 500 N
= 0.72 s
Now, according to First Formula of Motion,
v = u + at
⇒ a = v- u /t
= 0 m/ s - 20 m/s / 0.72 s
= - 20m/s / 0.72 s
= 27.77 m/s²
Finally, according to Third Formula of Motion
v² - u² = 2as
(0m/s)² - (20 m/s)² = 2×27.77m/s² × s
-400 m²/s² = 55.54 m/s² × s
s = -400 m²/s² / 55.54 m/s² = -7.2 m ( It is negative because displacement has direction, so when converting into distance, its absolute value is taken)
The scooter travels 7.2 m before coming to rest