Question

a car travelling at velocity 54 km for stops in 6 seconds after brakes are applied full stop how much force to the brakes apply to the car if its mass along with its driver is 800 kg.class9th science.force and laws of motion.​

Answer 1

Explanation :-

We are having with the information:-

Initial velocity is 54 km/hr

And it stops after brakes applied [Final velocity is 0]

Time taken is 6 s

Mass of the body is 800 kg

We need to calculate Force required for the body .

We can find the Force acting on the body by using Newton's second law .

F = m(v-u)/t

•F = Force acting

m = mass

v = final velocity

u = Initial velocity

t = time taken

Firstly let's convert the initial velocity km/hr - m/s

54km/hr = 54× 5/18 m/s

= 15 m/s

Initial velocity (u) = 15 m/s

Final velocity (v) = 0 m/s

Mass(m) is 800 kg

Time(t) is 6 s

Substituting in formula.

F = m(v-u)/t

⇒F = 800(0-15)/6

⇒F = 800(-15)/6

⇒F = 400 (-15) /3

⇒F = 400 (-5)

⇒F = -2000N

So, force required is -2000N .

[ - indicates the opposite direction]