What force arises from the physical contact of two objects?

A1200 kg car traveling north at 10 m/s is rear-ended by a 2000 kg truck traveling at 30 m/s. what is the total momentum before and after the collision?

During which interval are the persons represented by the graph not moving? a) 0 to 0.5 hrs b) 1.5 to 2 hrs c) 2 to 2.5 hrs d) 4.5 to 5 hrs

Which of the following is the main energy source for the sun? a. fission of hydrogen b. fusion of hydrogen c. fusion of helium d. fission of iron