Let the mass of the iron ball be m=100 g=0.1 kg and its velocity be v=10 m/s. The ball collides with the wall at an angle θ=30∘ with the wall.
The component of velocity perpendicular to the wall before the collision is vsin30∘.
Since the ball rebounds with the same angle, the component of velocity perpendicular to the wall after the collision is −vsin30∘ (assuming the collision is elastic).
The magnitude of the change in momentum of the ball along the normal is:
Δp=m(vsin30∘−(−vsin30∘))=2mvsin30∘
Substituting the given values:
Δp=2×0.1×10×sin30∘=2×1×0.5=1 kg m/s
The force experienced by the wall is equal to the rate of change of momentum (according to Newton's second law of motion) :
F=ΔtΔp
Given the period of contact Δt=0.1 s:
F=0.11=10 N
Thus, the force experienced by the wall is 10 N.