Chapter N3

Forces from Motion

Due Wednesday at start of class.

N2B.4, B.5, B.6

B.8 and B.9 due Friday

Diagrams

• Drawing the diagram correctly is an essential step in solving problems.

• Two types of diagrams must be drawn– Free body diagram– Net force diagram

Free body diagram

• Show only the forces that act on a single body– Do not show motion, etc.

• Show all the forces that act on the body

Net force diagram

• Determine the direction of the object’s acceleration (or that it is zero).

• Transfer the forces from the free body diagram to a single figure. Adjust the magnitudes of the forces in the diagram to be consistent with the direction of acceleration of the object.

Make free body and net force diagrams of each of the following:

1) Book at rest on table2) Car traveling at constant speed along a straight

road with air friction.3) Skier accelerating down hill with friction4) Box at rest on back bed of accelerating pickup5) Car going over the top of a circular hill at

constant speed6) Car going around a curve at constant speed.7) A car pushing a disabled truck so they

accelerate at a constant rate.Draw free body diagrams and net force diagrams for each vehicle..

Graphs of one dimensional motion

vx

t

t

ax

On your paper draw what the acceleration curve looks like.

Write on your paper a description of what is happening in each of these times.1 32

Graphs of one dimensional motion

vx

t

t

ax

On your paper draw what the acceleration curve looks like.

Write on your paper a description of what is happening in each of these times.

13

2

This is a basketball that has been dropped, and rebounds from the floor.

Draw the graphs for a car going at constant speed down the road and brakes to a stop and remains there.

vx

t

t

ax

N3 Problems due Friday

• N3B.3, B.4, B.6, B.8, B.9

• These problems will be discussed at the start of the period on Wednesday.