An object with a speed of 20. meters per second has a kinetic energy of 400. J. The mass of the object is

A. 1.0 kg

B. 2.0 kg

C. 0.50 kg

D. 40 kg

explain why

Option B. 2.0 kg

Explanation:

Data obtained from the question include:

V = 20m/s

K. E = 400J

m = ?

K. E = 1/2 mV^2

400 = 1/2 x m x (20) ^2

400 = 1/2 x m x 400

400 = m x 200

Divide both side by 200

m = 400/200

m = 2kg

The mass of the object is 2kg

2 Kg

Explanation:

∵ Kinetic Energy = 1/2 * (mass of object) * (velocity) ²

given Kinetic Energy = 400 Joules

velocity = 20 m/s

putting this given value of kinetic energy & velocity in the above equation

400 = 1/2 * (mass of object) * (20) ²

∴ mass of object = (400*2) / 400

mass of object = 2 Kg.

Hence option B is the correct answer