Question

1. 1. A 2 kg ball starts with a velocity of 4 m/s. After a force is applied to it for 5 s, its
velocity is 12 m/s. What is the force acting on the ball?

Answer 1

Answer:

F = 3.2[N]

Explanation:

This problem can be solved by applying the principle of conservation of linear momentum, where the original momentum plus the momentum applied on the body, will be equal to the final momentum. This can be interpreted by means of the following equation.

$(m_{1}*v_{1})+(F*t)=(m_{1}*v_{2})$

where:

m₁ = mass of the ball = 2 [kg]

v₁ = initial velocity = 4 [m/s]

F = force applied [N]

t = time = 5 [s]

v₂ = final velocity = 12 [m/s]

Now replacing:

$(2*4)+(F*5)=(2*12)\\8+5*F=24\\5*F=24-8\\5*F=16\\\\F=3.2[N]$