Question

What must be the velocity of a moving body of mass 2 kg so that its K.E is 25 J ?

Answer 1

we know,
kinetic energy is the half of product of mass and square of magnitude of velocity .
e.g K.E = 1/2mv²

where m is mass and V is magnitude of velocity .

now,

K.E = 1/2 mv²
25 Joule = 1/2 x 2 x v²

v² = 25 m²/s²
take square root both sides

v = 5 m/s

Answer 2

Given,

Kinetic energy (KE) = 25 J

Mass (m) = 2 kg


We know that,

Kinetic energy (KE) =1/2 mv²

25 = 1/2 * 2 * v²

v² = 25

v = √25

v = 5 m/s Ans.

Ans.) The velocity of a moving body is 5 m/s.