Motion

Speed, Velocity, and Acceleration

Frames of Reference The object or point from which

movement is determined Movement is relative to an object

that appears stationary Earth is the most common frame

of reference

Questions

What is the frame of reference for the sunset?

What is a frame of reference?

What is the most common frame of reference?

Question

When can you determine how fast you are going in a jet plane?

Motion Motion is a change in position

relative to a frame of reference Speed is the distance traveled

in a given amount of time Speed=distance time

Speed

The units for speed: meters/second (m/sec) kilometers/hour (km/hr) Speed that does not change

is constant speed

Average speed

Total distance divided by the total time

Formula: Total distance total time

Velocity Speed in a given direction Velocities in the same direction

combine by adding Velocities in different

directions combine by subtracting

Interesting fact

Rockets are launched in the same direction of the earth’s rotation to get an extra boost of 1800 km/hr to its speed

Questions What is motion? What is speed? How is it calculated?

What is average speed?

Questions

How is velocity different from speed?

Which two factors determine an object’s velocity?

Acceleration The change in velocity Acceleration is measured in

m/sec/sec or m/sec2

Formula is: (final velocity - original

velocity)/time

Deceleration vs. Acceleration A decrease in velocity is

deceleration or negative acceleration

A distance-time graph for acceleration is always a curve

Centripetal Acceleration

Acceleration directed toward the center of circular path

Questions What is acceleration? What is the shape of a

distance-time graph for acceleration?

What is centripetal acceleration?

Momentum Momentum is equal to the mass of an object times its velocity

momentum= mass x velocity

Conserving Momentum The law of conservation of momentum states that the total momentum is NOT lost, only transferred

Questions What is momentum? What happens to momentum

as the mass of a moving object increases?

What is the formula for momentum?

What is the law of conservation of momentum?