PHYS 1A Lecture 9: Lecture 5B Normal Force and Newton's third law

Which one of the following is true, according to Newton's laws of motion? Ignore friction.

a) A sports utility vehicle (SUV) hits a stationary motorcycle. Since it is stationary, the motorcycle sustains a greater force than the SUV does.

b) A semitrailer truck crashes all the way through a wall. Since the wall collapses, the wall sustains a greater force than the truck does.

c) Sam (18 years old) and his sister (9 years old) go ice skating. They push off against each other and fly apart. Sam flies off with greater acceleration.

d) Two astronauts on a spacewalk are throwing a ball back and forth between each other. In this game of catch, the distance between them remains constant.

e) None of these is true, according to the third law.