Physics, asked by muhammadrafiu6864, 10 months ago

A car of mass 2000 kg changes its speed from 72 km/h to 36 km/h in 5 seconds.the force applied by its brake is

Answers

Answered by vikram991
15

Given,

  • A Car of Mass(m) - 2000 kg
  • Initial Velocity of Car(u)  - 72km/h
  • Final Velocity of Car (v) - 36km/h

║Change km\h into m\s ║

\mapsto \sf{Initial\:Velocity = 72 \times \dfrac{5}{18} = 20m/s}

\mapsto \sf{Final\:Velocity = 36 \times \dfrac{5}{18} = 10m/s}

To Find,

  • The Force Applied by its brake .

Solution :

\longrightarrow We Know First Equation of Motion :

\bigstar \boxed{\pink{\sf{v = u + at}}}

Now Put the Value in this Equation :

\longmapsto \sf{10 = 20 + a \times 5}

\longmapsto \sf{10 - 20 = 5a}

\longmapsto \sf{-10 = 5a}

\longmapsto \sf{a = \dfrac{-10}{5}}

\longmapsto \boxed{\sf{a = -2m/s^{2}}}

Therefore,

\implies There is a Retardation of 2 m/s² due to Force applied by break.

Now We Find Force,

\longmapsto \boxed{\sf{Force  =mass \times acceleration }}

\longmapsto \sf{Force = 2000 \times -2}

\longmapsto \sf{Force = -4000N}

Therefore,

\implies The Force Applied by its brake is 4000N.

(Negative Sign Show the Opposite Direction)

\rule{200}2

Answered by Nereida
11

Answer :

Given -

  • Mass = 2000 kg
  • Speed changes from 72 km/hr to 36 km/hr
  • Time = 5 seconds

To Find -

  • Force applied by the brake ?

Solution -

Converting the speed given :

  • 72 * 5/18 = 20 m/s
  • 36 * 5/18 = 10 m/s

Finding acceleration : (v - u)/t

⇒ a = (10 - 20)/5

⇒ a = -10/5

⇒ a = -2 m/s²

Now, Force = Mass * Acceleration

➸ F = 2000 * -2

➸ F = -4000 N

Therefore, Force applied by the brakes on the car is 4000 N in the opposite direction.

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