Question

An object moving with a speed of 21 m/s and has a kinetic energy of 140 J, what is the mass of the object.

Answer 1

Answer:

Explanation:1/2mv2=140

M=140*2/21*21

=0.6

Answer 2

Given:

The speed of the object is 21m/s

The Kinetic energy (K.E) = 140 J

To Find:

Mass of the object = M

Solution:

As we know the formula for Kinetic energy is

K.E = ½MV²

where,

K.E is the kinetic energy of the object,

M is the mass of the object,

V is the velocity of the object.

Now, putting the values mentioned in the above equation, we get,

140 = ½xM x 21²

140 = ½ x M x 441

280 = M x 441

280/ 441 = M

M = 0.63492 Kg

M = 634.92 grams

Hence, the mass of the object with kinetic energy 140 J and velocity 21m/s is 634.92 grams.