Assignment: Speed Name:

Do the following activity using this web site

http://phet.colorado.edu/en/simulation/moving-man

Click on “The Moving Man”

·  After “The Moving Man” is open mess around with the controls a little. You can also manipulate the man directly.

1.  Describe what each element does on the Introduction tab

  1. Position
  2. Velocity
  3. Acceleration

·  Now click on the Charts tab at the top of the page

2.  Describe how data manipulation on this page is different from the Introduction.

  1. Explain when you’d prefer to use the Introduction page.
  2. Explain when you’d prefer to use the Charts page.

·  By either clicking on the man or the slider cause the man to move back and forth manipulate the data on the Charts tab.

3.  Observe what shows up on the graphs.

4.  Describe each of the Distance vs. Time, Velocity vs. Time and Acceleration vs. Time graphs for the actions below.

A.  A man moving from 0 to 10 at a slow steady pace.

a.

b.

c.

B.  A man moving from 0 to 10 at a fast pace.

a.

b.

c.

C.  A man standing still at 4 m

a.

b.

c.

D.  A man moving from 0 to 10 at a fast pace, then moving back to 0 at a slow pace.

a.

b.

c.

E.  A man moving from 0 to -10 at a fast pace the moving back to 0 at a slow pace.

a.

b.

c.

F.  A man moving from 10 to 0 at a fast pace.

a.

b.

c.

G.  Create your own scenario and describe the graphs that you created. When would you expect to see this type of graph in real life?

6. Below is a graph of a ball’s motion. Which of the following gives the best interpretation of the ball’s motion?

a.  The ball moves along a flat surface. Then it moves forward down a hill, and then finally stops.

b.  The ball doesn’t move at first. Then it moves forward down a hill and finally stops.

c.  The ball is moving at constant velocity. Then it slows down and stops.

d.  The ball doesn’t move at first. Then it moves backwards and then finally stops.

e.  The ball moves along a flat area, moves backwards down a hill and then it keeps moving.

7.  Which graph would best depict the following scenario? A man starts at the origin, walks back slowly and steadily for 6 seconds. Then he stands still for 6 seconds, then walks forward steadily about twice as fast for 6 seconds. Note that these are velocity-time graphs.

8.  For the same scenario as #7, which position-time graph best depicts the motion?

9.  A car is traveling along a road. Its velocity is recorded as a function of time and is shown in the graph below.

During which intervals is the car accelerating? Choose all the answers that apply.

a.  between 0 and 3 seconds

b.  for a brief instant at 3,8,13 and 17 seconds

c.  between 3 and 8 seconds

d.  between 8 and 13 seconds

e.  between 13 and 17 seconds

f.  between 17 and 20 seconds

10.  A car is moving forward and applying the break. Which position-time graph best depicts this motion?

11.  What kind of speed is registered by an automobile speedometer– average speed or instantaneous speed?

12.  If a car is moving at 90 km/hr and it rounds a corner, also at 90 km/hr.

a.  Does it maintain a constant speed?

b.  A constant velocity?

13.  What is the acceleration of a car that maintains a constant velocity of 100 km/hr West?

14.  Consider these measurements: 10 m, 10 m/s, and 10 m/s2. Which is a measure of distance, which of speed, and which of acceleration (the magnitude, without direction)?

15.  A. What is the impact speed when a car moving at 100 km/hr bumps into the rear of another car traveling in the same direction at 98 km/hr?

B. What if the two cars were headed in opposite directions– a head-on collision?

16.  Harry Hotshot can paddle a canoe in still water at 8 km/h. A. How successful will he be at canoeing upstream (north) in a river that flows at 8 km/h (south)?

B. How fast would he be moving, relative to a tree on the bank of the river, if he paddled downstream (south)?