Week 2 1

A car is driving at 35 m/s when it slams on its brakes, skidding and coming to a stop in 5.0 seconds.

a. Draw a motion diagram for this motion showing velocity and acceleration vectors

b. Graph position, velocity and acceleration versus time.c. Calculate the car’s acceleration.

d. How long will the skid marks be?

Week 2 2

Week 2 3

When jumping, a flea reaches a takeoff speed of 1.0 m/s over a distance of 0.50 mm.

What is the flea’s acceleration during the jump phase?

Week 2 4

When jumping, a flea reaches a takeoff speed of 1.0 m/s over a distance of 0.50 mm.

How long does the acceleration phase last?

Week 2 5

When jumping, a flea reaches a takeoff speed of 1.0 m/s over a distance of 0.50 mm.

If the flea jumps straight up, how high will it go? (Ignore air resistance here; in reality air resistance does play a role and the flea does not really go this high)

Week 2 6

A soccer player is juggling a soccer ball. The ball is kicked straight up at a speed of 8.0 m/s.

* Draw a motion diagram for the ball for the entire time it’s in the air. Include velocity and acceleration vectors.

* Graph the ball’s acceleration, velocity and position for the time while the ball is in the air.

* Calculate how long the ball is in the air before returning to its starting point and how high up it will go and use these numbers to label the axes of your graphs.

Week 2 7

Week 2 8

• Discover how and when objects accelerate

• Understand the meaning of acceleration, its magnitude and direction

• Discover the relationship between velocity and acceleration graphs

• Learn how to represent velocity and acceleration using vectors

• Learn how to find average acceleration from acceleration graphs

• Learn how to calculate average acceleration from velocity graphs

LAB 2 OBJECTIVES:

Week 2 9

You’ve trapped a soccer ball and give it a kick to pass it along the ground to your teammate. The ball slows a bit as it rolls through the grass.

Graph the ball’s velocity and acceleration during the kick and as it rolls along the grass.

Week 2 10

Week 2 11

A sailor sees a coconut tree on a distant island. She uses a sextant and measures the angle between the top of the coconut tree and the ground on the island to be 1.10o. If a typical coconut tree is 20 meters tall, approximately how far is the sailor from the island?

Week 2 12

You’ve walked 10 miles north and 5 miles east. What are the magnitude and direction of your net displacement?

Week 2 13

You find yourself 30 miles away from your campground, 67o west of north. How many miles north are you from camp? How many miles west?

Week 2 14

You walk 10 meters north and 15 meters northwest.

What are your coordinates with respect to where you started?

What’s your net displacement?

At what overall angle did you travel?

Week 2 15

Your car is turning a corner. You’re going north at 10 m/s at t=0 and you’re going east at 10 m/s when you finish the turn 2 seconds later.

What’s the magnitude and direction of your average acceleration during the turn?