Diagnostic Test for PET Curriculum Fall 2002

Name ______

Conceptual Pre-Test for PET Curriculum

1. A soccer goalie is practicing by punting a ball straight up into the air and then catching it again when it falls back down. Consider a moment just after the ball has been kicked, but is still moving upward (as shown in the picture). Which of the following forces do you think are acting on the soccer ball at this moment? (Choose all those that you think are present.)

a) A force of gravity pulling downward. b) A force from the kick pushing upward. c) A force of gravity pushing upward. d) A force pushing upward due to the motion of the ball. e) Some other force.

2. A hockey player uses his stick to maintain a constant strength push on the puck as he moves it across the smooth ice. Assuming that the effects of friction are negligible, which of the following choices best describes the motion of the puck while this constant strength push is acting on it?

a) The speed of the puck will continuously decrease. b) The puck will move at a constant speed. c) The speed of the puck will continuously increase. d) Something else.

PET Diagnostic Test 1 3. A large block is on rollers so that it can move across a surface as if there was no friction affecting it. After they have started the block moving to the right, two men want it to continue moving in the same direction, at a constant speed.

Below are drawings representing four possible situations. The arrows represent pulls that the men may exert on the box. In the diagrams the length of the arrows represent the strength of their pulls, and the direction of the arrows represents the direction of their pulls. The situations are also described briefly in words. Indicate all the situations shown (and described) below that you think would result in the block moving to the right at a constant speed after it has already started moving.

a) Pull to the right is stronger b) No-one pulls, either to the than the pull to the left. right or the left.

c) Pulls to the right and the left d) Only one person pulls to the are of equal strength. right. No-one pulls to the left.

PET Diagnostic Test 2 4-7 Jose has a toy wind-up car. Inside the toy car is a coiled spring. Jose holds the car on the floor, winds the spring up, and then lets the car go. He notices that the car speeds up quickly, then moves along the floor at a nearly constant speed for a while, then slows down to a stop.

Here are four possible statements that could be made about what was happening, in terms of energy, during various stages of the action described above.

A. Energy was being created. B. Energy was being destroyed. C. Energy was being transferred from one object to another. (State which objects are involved in your reasoning.) D. None of the above

During each of the following stages choose the best statement from those above to describe what you think was happening, in terms of energy. In each case also give your reasons for choosing the answer that you did.

4. While Jose was winding the spring up. (Energy was being transferred from one object to another) Energy from Jose is being transferred as he winds the toy car.

5. While the car was speeding up. (Energy was being transferred from one object to another) The energy that had been created in the spring when Jose wound up the car was transferred into the axel and wheels when the car was released by Jose.

6. While the car was moving along the floor at a constant speed. None of the above. All forces are equal.

7. While the car was slowing to a stop (but before it actually stopped). Energy was being destroyed. The friction from the floor is counteracting the energy of the moving car.

PET Diagnostic Test 3 4. Suppose you are standing close to your electric stove. You turn on one of the burners (heating element) to its high setting, and after several seconds you can feel your face being warmed. Right after you turn the burner off, what will happen—in terms of energy? a) The air around your face that has been warmed by the infrared radiation coming off of the hot burner will continue to warm your face for a while. b) The hot air that is touching the hot burner will rise up and warm your face for a while. c) The infrared radiation coming off of the hot burner will warm your face for a while. d) Once the burner is turned off, you face will not get any warmer.

PET Diagnostic Test 4