Question

A car of mass 2400 kg moving with a velocity of 20m/s is stopped in 10 seconds on applying brakes. Calculate the retardation and the retarding force.​

Answer 1

Answer:

The regarding force is 4800 N

Explanation:

we know Force=Mass*Acceleration

so here acceleration is (V-U) /t

where V is the final velocity and U is the initial velocity and t is the time.....

therefore acceleration=0-20/10

=-2m/s

here -2m/s is the retardation

and the retarding force is

F = ma

F =2400*(-2)

=-4800 N

Answer 2

Retardation produced in wheel be -2 m/s².

Magnitude of Retardation force will be - 4800 N.

Explanation :

Given :

m = 2400 kg

u = 20 m/s

v = 0 m/s

t = 10 s

To find :

The retardation produced and the magnitude of retarding force.

We know that :

$\bigstar\;\boxed{\bf{a = \dfrac{v-u}{t}}}$

So,

• Retardation produced :

$\implies \mathsf{a = \dfrac{v-u}{t}}\\ \\ \\ \implies \mathsf{ a = \dfrac{0 -20}{10}}\\ \\ \\ \implies \mathsf{a = \dfrac{-20}{10}}\\ \\ \\ \implies \mathsf{a = -2 m/s^2 }$

∴ Retardation produced in wheel be -2 m/s².

$\rule{300}{1.5}$

• Magnitude of retardation :

We know that we can find magnitude of retardation force by using 2nd law of Newton.

So,

$\implies \mathsf{ F = ma }\\ \\ \\\implies \mathsf{F = 2400 \times -2} \\ \\ \\\implies \mathsf{F = -4800 N}$

∴ Magnitude of Retardation force will be - 4800 N.