Answer: The mass of ball is 10 grams.
Step-by-step explanation:
Given : Kinetic energy = 4.5 J
Velocity = 30 m/s
The formula for Kinetic energy is as follows.
![K.E = (1)/(2)mv^(2)](https://img.qammunity.org/2022/formulas/physics/college/nycmfybh07rpugqnp638e50yr9cc06ekpb.png)
where,
K.E = Kinetic energy
m = mass
v = velocity
Substitute the values into above formula as follows.
![K.E = (1)/(2)mv^(2)\\4.5 J = (1)/(2) * m * (30 m/s)^(2)\\m = (4.5 J * 2)/(900 m^2/s^2) (1 Js^(2) = kg m^(2))\\= 0.01 kg (1 kg = 1000 g)\\= 10 g](https://img.qammunity.org/2022/formulas/physics/college/m119n6nd4yzl2mqraplofqh04k3n02byio.png)
Thus, we can conclude that the mass of ball is 10 grams.