Question

A car moves at a speed of 50 kilometers/hour. Its kinetic energy is 400 joules. If the same car moves at a speed of 100 kilometers/hour, then its kinetic energy will be 800 1,600 3,200 4,500 joules.

Answer 1

800 joules because it's twice the amount

Answer 2

If the same car moves at a speed of 100 kilometers/hour, its new kinetic energy will be 1600 Joules.

Step-by-step explanation:

Kinetic energy is defined as energy of a body due to its motion.

`K.E=(1)/(2)mv^2`

Where:

v = Velocity of the body in m/s.

m = Mass of the body

Given:

v = 50 km/h=
`(50 * 1000m)/(3600 s)=13.8 m/s`

1 km = 1000 m

1 hour = 3600 seconds

Kinetic energy of the body,K.E = 400 Joules

Mass of the body = ?

`400 J=(1)/(2)m(13.8)^2`

`m=(2* 400 J)/((13.8 m/s^)2)=4.1465 kg`

If the same car moves at a speed of 100 kilometers/hour, then its kinetic energy will be K.E'

New velocity of the car = v'=100 km/h =

=
`(100 * 1000m)/(36 s)=27.77 m/s`

`K.E=(1)/(2)* 4.1465 kg* (27.77 m/s)^2=1 1600 joules`

If the same car moves at a speed of 100 kilometers/hour, its new kinetic energy will be 1600 Joules.