Monday, October 29, 2012

Dynamics PBM Final Post

Question 1: Why does letting a small ball drop on top of a larger ball make such a dramatic difference in bounce?

Objectives:
1. The Physics Standards that relate to this problem are:
d. 
Students know
that when one object exerts a force on a second object, the second object always exerts a force of equal magnitude and in the opposite direction (Newton's third law).



e.
Students know the relationship between the universal law of gravitation and the effect of gravity on an object at the surface of Earth.

f.
Students know applying a force to an object perpendicular to the direction of its motion causes the object to change direction but not speed (e.g., Earth's gravitational force causes a satellite in a circular orbit to change direction but not speed).


h. *
Students know Newton's laws are not exact but provide very good approximations unless an object is moving close to the speed of light or is small enough that quantum effects are important. 



Why does letting a small ball drop on top of a larger ball make such a dramatic difference in bounce?

When a small ball is dropped on a larger ball, the smaller ball bounces dramatically higher than as the ball being dropped normally. This is the case because when both balls are dropped, the momentum of the larger ball is transferred to the smaller ball hence the increase of height. In addition, the smaller ball bounced higher because the force point caused it to go the opposite direction with the same magnitude at contact, resulting in the fast impact. With the help of inertia the objects stayed at rest and after the demonstration, the balls slowly return to the state of rest. The amount of force placed on the balls depends on how much mass and weight is in them. A bigger ball with more mass will make the smaller ball bounce higher than a small ball of the same weight with different mass. The one with more mass will work better with height reach because with more mass, the more force the ball will act on it.

Lab: Get balls with different masses and weight and compare the distance of the ball that goes up

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