Name: _________________________

PHY 151 Homework Solutions 05AName: _____________________

Newtons First Law

1.If a car is traveling due westward with a constant speed of 20 m/s, what is the resultant force acting on it?The first law tells that that if an object is traveling at constant speed in a straight line, there is no force acting on the object.

2.In the motion picture It Happened One Night, Clark Gable is standing inside a stationary but in front of Claudette Colbert, who is seated. The bus suddenly starts moving forward and Clark falls into Claudettes lap. Why did this happen?Let us assume that the bus exerts no force on Clark initially. As the bus move forward, Clark continues to be stationary. The bus moves towards Clark and it appears as if Clark falls backward onto Claudette.

3.A passenger sitting in the rear of a bus claims that she was injured when the driver slammed on the brakes, causing a suitcase to come flying toward from the front of the bus. If you were the judge in this case, what decision would you make (passenger truthful or passenger lying)? Why?The luggage and the bus are moving forward together. If the bus stops suddenly, the luggage continues to move forward. The luggage could not move backwards and hit the passenger. The passenger is lying.