Question

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

Answer 1

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

Answer 2

Option B. 2.0 kg

Step-by-step 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