Question

A motorcar is moving with a velocity of 108km/hr and it takes 4s to stop after the brakes are applied . Calculate the force exerted by the brakes on the motorcar if its mass along with the passengers is 1000kg

Answer 1

$\huge\bigstar\sf\underline\red{GIVEN:-}$

$\large\sf{u=180km/h}$

$\longrightarrow$$\large\sf{108×1000m/(60×60s)}$

$\longrightarrow$$\large\sf{30m/s}$

$\large\sf{v=0ms}$

$\large\sf{m=1000kg}$

$\large\sf{t=4s}$

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$\small\sf\orange{From\:eq,we\:have\:magnitude\:of\:the\:force\:(F)}$

$\small\sf\orange{applied\:by\:the\:brakes\:as\:m (\frac{v - u}{t} )}$

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$\small\sf\green{On\:substituting\:the\:values,we\:get}$

$\large\sf{F=\frac{1000kg \times (0 - 30)m/s}{4s} }$

$\implies$$\large\sf{-7500kg\:m/s\:or\:-7500N}$