### Unit 2: Motion and Forces

The velocity of an object is the rate of change of its position.
• Position is defined in relation to some choice of a standard reference point and a set of reference directions.
• Average speed is the total distance traveled divided by the total time elapsed; the speed of an object along the path traveled can vary.
• Solve problems involving distance, time and average speed.
• Velocity of an object must be described by specifying both the direction and the speed of the object.
• Changes in velocity may be due to changes in speed, direction, or both.
• Interpret graphs of position versus time and graphs of speed versus time for motion in a single direction.
Unbalanced forces cause changes in velocity.
• Force has both direction and magnitude.
• When an object is subject to two or more forces at once, the result is the cumulative effect of all the forces.
• When the forces on an object are balanced, the motion of the object does not change.
• Identify separately the two or more forces that are acting on a single static object, including gravity, elastic forces due to tension or compression in matter, and friction.
• When the forces on an object are unbalanced, the object will change its velocity (that is, it will speed up, slow down, or change direction).
• The greater the mass of an object, the more force is needed to achieve the same rate of change in motion.
• The role of gravity in forming and maintaining the shapes of planets, stars, and the solar system.

### Classwork

Simulators
Forces and Motion - pushing a crate against friction
Lunar Lander - accurately simulates the real lunar lander
Distance vs. Time Grapher - move the ball to make the graph in real time

#### Forces

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Kamyar Pourhamidi,
Jul 27, 2014, 7:04 PM
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Kamyar Pourhamidi,
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Kamyar Pourhamidi,
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Kamyar Pourhamidi,
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Kamyar Pourhamidi,
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