A motor cycle is moving with a velocity of 90km/hr and it takes 5 sec. to stop the brakes are applied. calculate the force exerted by the brakes on the motorcycle if its mass along with a rider is 200kg.
Answers
Explanation:
CORRECT QUESTION :-
★ A motorcycle is moving with a velocity of 90 km/h and it takes 5 seconds to stop after the brake applies. Calculatethe force exerted by the brakes on motorcycle if its mass along with the rider is 200 kg.
GIVEN :-
Initial velocity , u = 90 km/h.
Final velocity , v = 0 m/s.
Time , t = 5 seconds.
mass of body , m = 200 kg.
TO FIND :-
The force exerted by the brakes on motorcycle , F.
SOLUTION :-
★ Firstly we will convert the initial velocity in m/s.
→ initial velocity = 90 km/h
→ (90 × 1000)/3600
→ (90 × 10)/36
→ 900/36
→ Initial velocity = 25 m/s.
Now , As we know that,
→ Acceleration = (Final velocity - Initial velocity)/Time
→ a = (v - u)/t
→ a = (0 - 25)/5
→ a = -25/5
→ Acceleration = -5 m/s².
Note :- The negative sign (-ve) indicates retardation of Acceleration.
Now as we know that,
→ Force = mass × Acceleration
→ F = ma
→ F = 200 kg × -5 m/s²
→ F = -1000 kg × m/s²
→ F = -1000 N.
Hence The force exerted by the brakes on motorcycle is (-1000) Newtons.