Question

the kinetic energy of a body is 20 joule and it's speed is 12 m/s, what will be it be mass​

Answer 1

Provided that:

• Kinetic energy = 20 J
• Speed = 12 mps

To calculate:

• The mass

Solution:

• The mass = 0.27 kg

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 velocity.

Required solution:

$:\implies \sf E_k \: = \dfrac{1}{2} \: mv^2 \\ \\ :\implies \sf 20 = \dfrac{1}{2} \times m(12)^{2} \\ \\ :\implies \sf 20 = \dfrac{1}{2} \times m(144) \\ \\ :\implies \sf 20 = \dfrac{1}{2} \times 144m \\ \\ :\implies \sf 20 = 1 \times 72m \\ \\ :\implies \sf 20 = 72 m \\ \\ :\implies \sf m \: = \dfrac{20}{72} \\ \\ :\implies \sf m \: = 0.27 \: kg \\ \\ :\implies \sf Mass \: = 0.27 \: kg$