Motion and Speed

Objects move relative to other objects Video *Motion – Changing position relative to a

fixed point

What is motion?

*Speed – how fast an object is moving

Speed

Ex 1 A cheetah covers 50 meters in 2 seconds.

What is the cheetah’s speed? Speed = D/T Speed = 50 m / 2 s Speed = 25 m/s

Let’s Practice!

Ex 2 A red corvette is speeding down the

highway at 150 km/hr. If it continues at this speed for 1.5 hours, how far has it gone?

Speed = d/t 150 km/hr = d/1.5 hrs 1.5 hrs*150 km/hr = d 225 km = d

Let’s Practice!

*Instantaneous Speed – speed at a specific moment in time

*Average Speed – average speed over a given period of time

Speed

A hedgehog wakes up at 10:23. As soon as he wakes up, he starts sauntering towards some bugs to eat. After three seconds, he is moving at 0.5 m/s. After 10 seconds, he has moved 2 meters from where he started.

A. What is the hedgehog’s instantaneous speed after three seconds?

B. What is the hedgehog’s average speed over the 10 second interval?

Let’s Practice!

Book page 62 #1-4, 26-31 

Homework

In groups of 2-3, go to a computer and use the motion detectors to complete the “lab activity” posted on the website.

Motion Detectors