Question

solve and tell it's answer

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Answer 1

FIRST WE HAVE TO FIND THE ACCELERATION IN ORDER TO USE F=ma FORMULA TO FIND THE FORCE.

Given

mass of car= 1000kg

initial velocity of car before stopping (u)= 108km/h

or 30m/s (to convert km/h to m/s we need to multiply it by

$\pink{ \frac{5}{18} }$

time (t)= 4s

final velocity after stopping (v)= 0m/s

Working

acceleration (a)=

$\blue{ \frac{v - u}{t}}$

=

$\blue{ \frac{ 0 - 30}{4}}ms ^{2}$

acceleration= (-30/4)ms²

Now we can find the force exerted by the brakes to the car of weight 1000kg using the formula derived by the Newton's second law of motion-->F=ma. Where F stands for force, m stands for mass, a stands for acceleration.

$\green{f = ma}$

F= 1000Kg (m) x (-30/4)ms² (a)

F= -7500kgms²

or simply -7500N

the negative sign shows that the force is in opposite direction of motion.

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