Question

a truck of mass 500kg , decreases its speed from 54km/h to 36km/h . find the decrease in its kinetic energy​

Answer 1

Given :-

• A truck of mass = 500 kg

• It speeds decreases from 54km/h to 36km/h

Solution :-

Here, we have to find decrease in Kinectic energy

Therefore,

Change in Kinectic energy

= 1/2m(vf^2 - vi^2 )

Here

Mass = 500 kg

Initial velocity = 54km/h

Final velocity = 36km/h

As we know that,

SI unit of distance is m/s

Therefore,

V1 = 54km/h = 54 * 5/18 = 15m/s

V2 = 36km/h = 36 * 5/18 = 10m/s

Now,

Change in Kinectic energy

= 1/2 * 500( 10 * 10 - 15 * 15 )

= 1/2 * 500 ( 100 - 225 )

= 1/2 * 500 * (- 125 )

= 250 * ( -125 )

= - 31.25 KJ $.$

Hence, The decrease in its Kinectic energy is - 31.25 KJ

Formula kept in Mind :-

• Kinectic energy = 1/2mv^2

Answer 2

Answer:

Given :-

• A truck of mass = 500 kg

• It speeds decreases from 54km/h to 36km/h

Solution :-

Here, we have to find decrease in Kinectic energy

Therefore,

Change in Kinectic energy

= 1/2m(vf^2 - vi^2 )

Here

Mass = 500 kg

Initial velocity = 54km/h

Final velocity = 36km/h

As we know that,

SI unit of distance is m/s

Therefore,

V1 = 54km/h = 54 * 5/18 = 15m/s

V2 = 36km/h = 36 * 5/18 = 10m/s

Now,

Change in Kinectic energy

= 1/2 * 500( 10 * 10 - 15 * 15 )

= 1/2 * 500 ( 100 - 225 )

= 1/2 * 500 * (- 125 )

= 250 * ( -125 )

= - 31.25 KJ ..

Hence, The decrease in its Kinectic energy is - 31.25 KJ

Formula kept in Mind :-

• Kinectic energy = 1/2mv^2