Question

Your forehead can withstand a force of about 6.0 kN before fracturing, while your cheekbone can only withstand about 1.3 kN .
Part A -
If a
140 baseball strikes your head at 30 m/s and stops in 0.0015s , what is the magnitude of the ball's acceleration?
Part B -
What is the magnitude of the force that stops the baseball?
Part C -
What force does the baseball apply to your head? Explain?
Part D -
Are you in danger of a fracture if the ball hits you in the forehead? Cheek?

Answer 1

a) accelertaion of base ball = 30/0.0015 = 20,000 m/s^2 apprx
b) Force on base ball= 0.140 kg x 20,000= 2800 N = 2.8 kN
c) 2800 N
d) No danger with forhead but yes cheek bone will break

Answer 2

a) magnitude of acceleration = velocity/time = 30/0.0015 = 20k m/s²

b) F = ma = 0.140kg * 20k = 2.8k N

c) The force applied is 2.8k N.

d) You are not in danger of having a fracture in your head. However, you are in danger of having a fracture in your cheek.