MotionPg. 322-332 in your textbook.

What is Motion?• All matter in the universe is constantly in

motion, from the revolution of Earth around the Sun to electrons moving around the nucleus of an atom.

• Anything in motion changes position.

• Speed is the distance traveled divided by the time it takes to travel that distance.

Speed

• Speed is calculated from the following equation:

Speed Practice #1

• This motorcycle travels 100-m in 10.2 seconds. What is the speed of this motorcycle to the nearest 10th?

• Answer: 9.8 m/s

Speed Practice #2

• A runner completes a 400-m race in 43.9 s. In a 100-m race, he finishes in 10.4 s. In which race was his speed faster (nearest 10th)?

• Answer: The runner’s speed was 9.1 m/s in the 400-m race and 9.6 m/s in the 100-m race. Therefore, he is faster in the 100-m race.

• Velocity is the speed of an object and the direction of its motion.

Velocity

• Velocity is calculated using the speed equation AND direction.

• This would be used, for example, if you were hiking in the woods since you would want to know your speed AND the direction you were moving.

Velocity Practice

• Calculate the velocity of a dancer who moves 5 ft to the left of the stage over 15 min (nearest hundredth).

• Answer: 0.33 ft/min left

• Acceleration is the change in velocity divided by the time it takes for the change to occur.

Acceleration

• Acceleration is calculated from the following equation:

Acceleration

Acceleration Practice #1

• A bicycle accelerates from rest to 6 mi/s in 2 s. What is the bicycle’s acceleration?

• Answer: 3 mi/s2.

Acceleration Practice #2

• Find the acceleration of a train whose speed decreases from 17 m/s to 7 m/s in 120 s (nearest thousandth).

• Answer: -0.083 m/s2