A student throws a 120 g snowball at 7.5 m/s at the side of the schoolhouse, where it hits and sticks. Part A What is the magnitude of the average force on the wall if the duration of the collision is 0.18 s? Express your answer to two significant figures and include the appropriate units.

5.00 N

Explanation:

Force: This is defined as the product of mass and acceleration. The S. I unit of Force is Newton (N).

Mathematically,

F = ΔM/t ... Equation 1

Where F = Force needed to stop the snowball, ΔM = change in momentum, t = time.

But

ΔM = mΔv

ΔM = m (v-u) ... Equation 2

Where m = mass of the snowball, Δv = change n velocity of the snowball, u = initial velocity, v = final velocity.

Substituting equation 2 into equation 1

F = m (v-u) / t ... Equation 3.

Given: m = 120 g = 120/1000 = 0.12 kg, v = 0 m/s, u = 7.5 m/s, t = 0.18 s

Substituting into equation 3,

F = 0.12 (0-7.5) / 0.18

F = - 0.9/0.18

F = - 5.00 N.

From newtons third law of motion,

The Force need to stop the ball is equal and opposite to the force on the wall (Average force by the ball)

Therefore,

The average force on the wall = 5.00 N in opposite direction to the motion of the snowball