College Physics I - Test 1a - 10/29/03

Name: ________________________________________________________

Read the exam over carefully. Then do the easiest ones first.

Do the problems on your scratch paper as you would normally and then fill in the blanks below as required. DO NOT WORK THE PROBLEMS ON THE TEST SHEET. Problems solved on the scratch paper but not filled in below will not be graded.

Numerical answers must either be expressed as decimal numbers or in correct scientific notation or they will be marked incorrect. All answers which are physically unreasonable will be marked incorrect.

The following graphs may be useful:

1. What is the acceleration of the red ball relative to that of the black? _greater__
   
2. We need an equation for time as a function of distance and acceleration.
   The time is measured in s.
   The distance is measured in m.
   The acceleration is measured in m/s^2.
   There is a unitless factor of 2 in this equation.
   Construct the equation and prove that the units are the same on both sides.

   Answer:

   
   __________________t = (2 x / a) ^ (1/2)______________________________________________

   Units:

   
   __________________s = (m / (m / s^2)) ^ 1/2__________________________________________

3. You have fallen from a height of 6.149 m.
   Your fall was broken in 0.00359 s.
   Your mass is 66.38 kg.
   What force did you experience as you stopped?

   Equations:

   
   __________________t = (2 h / g) ^ (1/2)______________________________________________

   
   __________________v = - g t__________________________________________________________

   
   __________________a = - v / tstop____________________________________________________

   
   __________________F = m a____________________________________________________________

   Variable Assignments:

   
   ____h = 6.15 m___________g = 9.8 m/s^2___________tstop = .0036 s_____________________

   
   ____m = 66.4 kg______________________________________________________________________

   Answer, with units:

   
   ___________F = 2 * 10^5 N____________________________________________________________

4. You have fallen from a height of 3.079 m.
   Your mass is 65.18 kg.
   Your fall was broken in 0.00595 s.
   How much power was expended as you stopped?

   Equations:

   
   __________________U = m g h__________________________________________________________

   
   __________________P = U / t__________________________________________________________

   
   _____________________________________________________________________________________

   
   _____________________________________________________________________________________

   Variable Assignments:

   
   ____m = 65.2 kg__________g = 9.8 m/s^2___________h = 3.08 m__________________________

   
   ____t = .006 s_______________________________________________________________________

   Answer, with units:

   
   ___________P = 3.3 * 10^5 W__________________________________________________________