Question

what is the kinetic energy of a 70 kg car moving at a speed of 30 m/s?

Answer 1

Provided that:

• Mass of car = 70 kg
• Speed of car = 30 mps

To calculate:

• The kinetic energy

Solution:

• The kinetic energy = 31500 J

Using concept:

• Kinetic energy formula

Using formula:

• ${\small{\underline{\boxed{\pmb{\sf{E_k \: = \dfrac{1}{2} \: mv^2}}}}}}$

Where, E_k denotes kinetic energy, m denotes mass and v denotes speed.

Required solution:.

$:\implies \tt E_k \: = \dfrac{1}{2} \: mv^2 \\ \\ :\implies \tt E_k \: = \dfrac{1}{2} \times 70 \times (30)^{2} \\ \\ :\implies \tt E_k \: = \dfrac{1}{2} \times 70 \times 900 \\ \\ :\implies \tt E_k \: = \dfrac{1}{2} \times 63000 \\ \\ :\implies \tt E_k \: = 31500 \: Joules \\ \\ :\implies \tt Kinetic \: energy \: = 31500 \: Joules$

• Energy that possess during the motion of the body is known as kinetic energy.

Answer 2

Answer:

KE = 31500 J

Explanation:

The kinetic energy is  K E = 1 /2 m v ^2

The mass is  m = 70 k g

The velocity is  v = 30 m/s

So,

K E =1 /2 ⋅70  ⋅ 30^2  

= 31500 J