Physics 321 -- Spring 2006
Homework #2, due Wednesday
Jan. 25 at beginning of class
1. [4pts] Marion & Thornton, problem 2-29.
(An “8% grade” means that the vertical distance is
0.08 when the horizontal distance is 1.0 .)
2. [4pts] Marion & Thornton, problem 2-41.
It is possible to do this problem in your head and just
write down the answers. If you do that,
then check your answers to parts (c) and (d) in the following way. Assume that the woman exerts a constant
force F on the ball during a time T.
Express F in terms of m, v, and
T using Newton’s 2nd
Law, then calculate the work done by the force F and check that it matches your
result to part (c). For part (d),
notice that the horizontal force the train exerts on the woman while she throws
the ball is the same F as above. From
that F, calculate the work done by the train on the woman while she throws the
ball, and check that it equals your answer to part (d). Hint: How far does the woman move with
respect to the ground while she is throwing the ball?
3. [4pts] Marion & Thornton, problem 2-40.
“Tangential acceleration” is the component of the acceleration in the
direction of the velocity.
“Normal acceleration” is the component of acceleration
perpendicular to the velocity.
4. [4pts] Marion & Thornton, problem 2-47. (The constants
"a" and "alpha" are supposed to be the same.)
After doing the problem as stated, answer the
following questions assuming the particle has a total energy of 3 Joules and
a mass of 0.2 kg:
(a) What are the limits of its motion in the
potential?
(b) What is its
speed when it passes the point x=3 m?
5. [4pts] Marion & Thornton, problem 2-22.