Kinematics – Linear Motion Topics Point of Reference Speed – Velocity - Acceleration Free Fall – How Far?, How Fast? Graph of Motion Activities Class Work Problem Solving

Frame of Reference Plane: 200 Km/h E Car : 50 Km/h E Plane: 200 Km/h E Car : 50 Km/h E

Frame of Reference Plane: 200 Km/h W Car : 50 Km/h E Plane: 200 Km/h W Car : 50 Km/h E

Speed - Velocity Instantaneous speed - the speed that something has at any one instance

The average speed for a trip might be 53 miles/hour.... or 70 miles/hour on the open road. However, during this trip your instantaneous speed might have been 0 miles/hour at a stoplight... Speed - Velocity Velocity = {speed with a direction} Examples: 70 Km/h is a speed. 70 Km/h North is a velocity.

Acceleration - rate of change in velocity due to change in speed or direction Acceleration m/s m s s 2 ==

Example Question 1. What is the average speed of a cheetah that sprints 100 meters in 4 seconds? 2. How about if it sprints 50 m in 2 s? If a car moves with an average speed of 60km/h for an hour, it will travel a distance of 60 km. –(a) How far would it travel if it moved at this rate for 4 hours? –(b) For 10 h? –(c) Would it be possible for the car to have an average speed of 60km/h and never exceed a reading of 60km/h?

The speedometer of a car moving to the east reads 100km/h. It passes another car that moves to the west at 100km/h. Do both cars have the same speed? Do they have the same velocity? During a certain time, the speedometer of car reads a constant 60km/h. Does this indicate a constant speed? Constant velocity? Example Question

Free Fall A free-falling object is an object which is falling under the sole influence of gravity. Free-falling objects do not encounter air resistance. All free-falling objects (on Earth) accelerate downwards at a rate of 9.8 m/s 2 (often approximated as 10 m/s 2 ) How Fast ? V = g. t

Example Question What will be the speed of a freely- falling object after falling 6 seconds? 7 seconds? 8 seconds? Answer: Each second its speed increases by 10 m/s, so in 6 seconds its speed is 60 m/s; in 7 seconds, 70 m/s; in 8 seconds, 80 m/s. Here of course, we ignore air drag (which depends on the nature of the object).

Question 1 Does the acceleration of a ball depend on how fast it is thrown initially? Answer: No! The speed of the ball does, but not the acceleration. Note that each second the speed changes by 10 m/s, decreasing on the way up and increasing on the way down, whether it is moving fast or slow. Answer: While going up and while coming down, the acceleration is downward - toward the center of the earth. While going up, the direction of the ball is " against“ the direction of acceleration; while coming down, the direction of the ball's motion is "with " the direction of acceleration. In which direction is the ball accelerating while going up? While coming down?

Free Fall – How Far?

Motion Graphs Constant Velocity Changing Velocity (acceleration) Constant Velocity – going forwardConstant Velocity – going fasterConstant Velocity – going backward