Physics 5 - Spring 1998 Test 2

1. Shown is a multiple flash photo of two balls taken in equal time intervals of one second. Each small division is one meter.

a) Describe the motion of the lower (white) ball in terms of its velocity and acceleration during the 8 time intervals shown: 1-2, 2-3, etc.... list intervals in which ball is accelerating, constant speed, and decelerating.

b) Plot the velocity of the upper (black) ball for the seven intervals shown. The velocity for the first interval (1-2) is already plotted.

2. The ball moves from a to e along the path shown and is shown in equal time intervals.

a) Draw appropriate velocity vectors on the ball at points a, b, and c.

b) At point d, draw vectors representing the acceleration "along the path" and "perpendicular to the path". Add them (rectangle) to show total acceleration.

3. Identiy the correct statements. Correct the incorrect statements. According to Newton:

a) The gravitational force explains why planets go around the sun

b) A body with no net force on it must be at rest.

c) There must always be a force in the direction of motion.

d) Two bodies that interact must always exert equal and opposite forces on each other.

e) The moon is falling with a gravitational acceleration of 9.8 m/s/s.

4. a) Draw and label all the forces acting **on** box
B which is being accelerated across the rough table top with the string
shown.

b) Name the third law reaction forces to each of the forces you labeled on body B.

5. a) The ball is moving around the circular track which is resting on a horizontal tabletop. When the ball comes out of the tube, which of the paths would it take? Choose the path and say why you chose it using Newtons Laws.

Path ____ because

Is a ball which is thrown up into the air accelerating at the top of its path? Explain your answer.

6. An object moves according to the graph of velocity vs time shown

a) What is the acceleration during the first 3 seconds?

b) What is the area of one square on the graph? Include units.

c) How far did the object travel during the first 5 seconds?

7. On the planet Ikky, a freely falling object was observed to be traveling at a velocity of 12 m/s at the end of 2 seconds when it was 12 meters below the point of release. Include units in all your answers.

a) How far did the object fall in the first second and how fast was it traveling?

b) What is the acceleration due to gravity on the planet?

c) How far will the object fall during the 3rd second?

8. a) You are pushing a disabled truck as shown with an
acceleration of 1 m/s/s. Show and label the forces **on** your car which
allows you to accelerate.

b) State Newtons 2nd Law which tells you that you can accelerate forward. Show the relation between the forces on the car "along the path of motion" that must exist to be able to accelerate forward.