Question

Calculate the work required to done to stop a car of 1500 kg moving at a velocity of 60 km per hour?

Answer 1

Hi.

Here is your answer---

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Given---

Mass(m) = 1500 kg.
Initial Velocity(u) = 60 km/hr.
                           = 60 × (5/18).    [Changing into m/s.]
                           = 50/3 m/s.
Final Velocity(v) = 0   [ Since the Car is Stopped]

Using the Work Energy Theorem,

Work done = 1/2 × m( v² - u²)
                  = 1/2 × 1500( 0 - {50/3}²)
                  = - 208333.33 J

Thus, Work will be done in Opposite direction of the Motion of the Car(as it is negative) and it will be Equals to 208333.33 Joules or 208.4 KJ.

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Hope it helps.

Have a nice day.

Answer 2

Hey there!

Given,

Mass of car (m) = 1500 kg

Velocity of car ( v) = 60 km/h = 60 * 5/18 m/s

Work done = ?

Here,

Work done = Kinetic Energy

                  = 1/2 * mv²

                  = 1/2 * 1500 * 60 * (5/18) J

                  = 20.8 × 10⁴ J (←Answer)

Hope It Helps You!