Question

In a running race competition, a student who is weighing 40 Kg is running at 4m/s. Calculate the Kinetic energy of the student.​

Answer 1

Information provided with us:

• In a running race competition, a student is weighing 40 Kg.
• That student is running at 4m/s.

What does we have to calculate:

• Kinetic energy of that student who is running.

Here formula of kinetic energy would be used by us,

• $\red \bigstar \: \underline{ \boxed{\sf{K.E. \: = \: \dfrac{1}{2} \: mv {}^{2} }}}$

Here,

• K is kinetic energy
• m is mass of the body
• v is velocity

Again we have,

• Velocity is 4m/s
• Mass is 40 kg

Now,

$: \longmapsto \: \sf{K.E. \: = \: \dfrac{1}{2} \: \: 40(4){}^{2} }$

$: \longmapsto \: \sf{K.E. \: = \: \dfrac{1}{2} \: \: 40 \times (4){}^{2} }$

$: \longmapsto \: \sf{K.E. \: = \: \dfrac{1}{2} \times 40 \times 4 \times 4}$

$: \longmapsto \: \sf{K.E. \: = \: \dfrac{1}{ \cancel2} \times \cancel{ 40} \times 4 \times 4}$

$: \longmapsto \: \sf{K.E. \: = \: 1\times 20 \times 4 \times 4}$

$: \longmapsto \: \sf{K.E. \: = \: 20 \times 4 \times 4}$

$: \longmapsto \: \sf{K.E. \: = \: 20 \times 16}$

$: \longmapsto \boxed{\: \bf{K.E. \: = \: 320}}$

• Hence, kinetic energy of the student whose weight is 40kg and velocity is 4 m/s is 320kg m²/s²

Answer 2

Answer: 320 kgm/s^2

Explanation: kinetic energy = 1/2 * mv^2

                      kinetic energy = 1/2 * 40*(4*4)

                                               =  1/2 * 40*16

                                               =    1/2 * 640

                         kinetic energy = 640/2

                          kinetic energy = 320 kg m/s^2