Physics 213 Quiz # 1 5 points each Wednesday 8-30-2006

1. Define distance.

2. Define displacement.

3. Define speed.

A motorist wishes to travel 40 kilometers at an average speed of 40 km /hr. During the first 20 kilometers he travels an average speed of 40 km/hr. During the next 10 km he travels 100 km/hr.

4. How much time does she have left to finish the trip if she is to average 40 km / hr ?

5. With what average speed must she travel during the last 10 km in order to average 40 km /hr over the entire trip?

6. All snow cricket chirp at the same rate at the same temperatures. Below 0^o C they go into hibernation, above 100^o C their chirp rate begins to drop off dramatically as the crickets begin to fry. Below is a chirp rate vs temperature table.

Is chirp rate proportional to temperature?

If so, what is the constant of proportionality?

T(^oC)	0	20	40	60	80	100
C(chirps/s)	0	80	160	240	320	400

Draw A + B and A -B for each pair of vectors in problems 7 & 8.

Remember, the vectors on this page are real vectors, meaning you can redraw them elsewhere, but you cannot change their direction or magnitude. Make certain you make it absolutely clear to me what you mean by A + B and A - B .

7. 8.

9. The density of aluminum is 2.70 x 10³ kg/m³ and the density of iron is 7.86 x 10³ kg/m³. Find the radius of a solid aluminum sphere that will balance a solid iron sphere of radius 2.00 cm on an equal arm balance.

10. Draw the velocity vs time graph for the given displacement vs time graph.

5 pts bonus: Describe the motion in words. for problem 10.