Question

6. Brakes are applied to a car of mass 1000 kg traveling at a rate of 20 msl. This reduces the
speed of the car to 10ms in 5 second. Find the force exerted on the car by the brakes.​

Answer 1

Answer:

160 m

Explanation:

Initial speed of the car is u.

Final speed of the car v=0

Let the retardation of the car be a.

Using v2 −u2 =2aS

Or 0−u =2aS

⟹ S∝u2 (for same a)

Given : S=40m u' =2u

S'/S =(u')2/u2 =2the power 2

S'/40 = 4

S' =160m

Answer 2

Answer:

F = 2000 N

Explanation:

mass = 1000 kg

initial velocity = 20 m/s

final velocity = 10 m/s

time = 5 sec

Force = ?

Force = mass x acceleration

F = m x a

F = 1000 x [(u-v)/t] ................ [Formula used a = (v-u)/t]

F = 1000 x [(20-10)/5]

F = 1000 x 2

F = 2000 $\frac{Kg m}{s^{2} }$

F = 2000 N