Newton's Laws PREFLIGHT

The following three questions refer to the material you were to read in preparation for the lesson.

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# 1. Multiple Choice

A free-body diagram is a sketch showing an object and all of the forces being exerted on it. Always draw a free-body diagram when you are analyzing forces.

At Rest:
Constant Velocity:

A box is at rest on a flat table. Which free-body diagram is correct?
(1) mg down and N up
(2) mg down, N up, some other force F to the right
(3) mg down, N up, equal-and-opposite forces left and right
(4) could be either (1) or (3)

A box is moving at constant velocity to the right. Which free-body diagram is correct?
(1) mg down and N up
(2) mg down, N up, some other force F to the right
(3) mg down, N up, equal-and-opposite forces left and right
(4) could be either (1) or (3)

In both cases above, mg and N are equal in magnitude and opposite in direction. Are these the equal-and-opposite forces discussed in Newton's Third Law?
Yes
No
Neither, explain below

# honors extra

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What is the mass of the glider on the air track, if the hanging weight has mass of 20 grams? Friction is negligible. (Use the positions, given in meters, shown next to the glider and weight. Time is given in seconds.)

Below is a space for your thoughts, including general comments about today's assignment (what seemed impossible, what reading didn't make sense, what we should spend class time on, what was "cool", etc.):

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I received no help from anyone on this assignment.