PHYS 101

Homework # 5 Due: Thursday March 24 in class.

1.- Can you ride your bike on a circular highway at constant speed? How about at constant velocity? Explain the difference.

2.- Two balls (red and black) are set to roll on opposite sides of a meter stick (each number is a centimeter). A camera is installed and it is set so that it takes one picture every three seconds starting at time t = 0 sec, when the balls begin to roll..

The superimposition of the images looks like this:

a.- Is the black ball accelerating? Why?

b.- Is the red ball accelerating? Why?

c.- What are the average speeds of the black ball and that of the red ball?

d.- What is the position on the ruler of the black ball at t = 7.5 seconds?

e.- And that of the red ball?

3.- A cyclist travels 28 kilometers in 20 minutes. Calculate the average speed of the cyclist in meters per second

4.- A car accelerates, at a uniform rate of acceleration, from 0 km/h to 84 km/h in twelve seconds

What is this car’s acceleration? Give your answer in both km/hour/sec and m/second2

5.- - Consider a situation with similar setup as in problem 2. Here the pictures are taken once every second, starting at t = 0 sec, both balls start at time t = 0, from x = 0 and from rest.

a.- Is the black ball accelerating? Why?

b.- What about the red ball? Is it accelerating?

c.- What is the acceleration of the black ball? (Hint assume the acceleration is constant)

d.- What is the acceleration of the red ball?