Answer: The mass of ball is 10 grams.
Explanation:
Given : Kinetic energy = 4.5 J
Velocity = 30 m/s
The formula for Kinetic energy is as follows.
[tex]K.E = \frac{1}{2}mv^{2}[/tex]
where,
K.E = Kinetic energy
m = mass
v = velocity
Substitute the values into above formula as follows.
[tex]K.E = \frac{1}{2}mv^{2}\\4.5 J = \frac{1}{2} \times m \times (30 m/s)^{2}\\m = \frac{4.5 J \times 2}{900 m^2/s^2} (1 Js^{2} = kg m^{2})\\= 0.01 kg (1 kg = 1000 g)\\= 10 g[/tex]
Thus, we can conclude that the mass of ball is 10 grams.