linear motion

LINEAR

MOTION

6. Can an object have a constant speed and a varying velocity at the same time? Explain.

1. What is motion? How is motion relative? Is it enough to say that motion is a change in position?

2. How is instantaneous speed different from average speed?

3. Does a car speedometer measure speed, velocity or both? How about the odometer?

4. Does a change in the speed of an object always produce a change in its velocity? Why?

5. When does motion become accelerated?

6. Is it possible to have a constant speed but changing velocity? Give a situation.

7. What is acceleration?

How do we calculate acceleration?

average speed:a.) Vs = d/taverage velocityb.) V = d/taverage acceleration

c.) a = vf - vi t

For uniformly accelerated motion:

d.) d = [ vf + vi ] t 2

e.) d = vit + ½ at2

f.) vf = vi + at g.) vf2 = vi2 + 2ad

Using a 5 column table, check the variables that are present in the formula and put an x on the variable that is asked for. Ex:

d vf

vi

a t

x

1. Rachel wants to go outside but there is a thunderstorm. She sees the flash of lightning bolt and begins counting the seconds until she hears the clap of thunder 5.0 seconds later. She knows that the speed of sound in air is 340 m/s. How far away is the lightning?

2. Albert is riding his scooter at a velocity of 80 km/ hr, when he sees an old woman crossing the road 45 m away. He immediately steps hard on the brakes to get the maximum deceleration of 7.5 m/s2. How far will he go before stopping? Will he hit the old woman?

3. A driver traveling at 70 km/h tries to stop the car and finds that the brakes have failed. The emergency brake is then pulled and the car comes to a stop in 120 m. Find the car’s deceleration..