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.

0.635 kg

Explanation:

Recall that Kinetic energy is defined as:

K.E. = (1/2) mv²,

where

K.E = Kinetic energy = given as 140J

m = mass (we are asked to find this)

v = velocity = given as 21 m/s

Substituting the above values into the equation:

K.E. = (1/2) mv²

140 = (1/2) m (21)²   (rearranging)

m = (140)(2) / (21)²

m = 0.635 kg

answer; i believe the correct answer is (40,000 j) good luck

inverse v=i*r

nice nice