University Physics (OpenStax) Vol 1, 2021
P2311 Homework 9 (Ch. 9)
Assigned:
Problems
Ch. 9 Concept Q's: 1, 3, 11,13
Problems: 18,21,25,26,29,30,31,32,37,41,42,43,53,54,63,69
Ch. 9 Concept Qs:
1. Since K=p^2/2m, then if the momentum is fixed, the object with
the smaller mass has more kinetic energy.
3. Yes; impulse is the force applied multiplied by the time during which
it is applied (J=F Delta t), so if a small force acts for a long
time, it may result in a larger impulse than a large force acting
for a small time.
11. No, he is not a closed system because a net nonzero external force acts
on him in the form of the starting blocks pushing on his feet.
13. Yes, all the kinetic energy can be lost if the two masses come to rest
due to the collision (i.e., they stick together).
Ch 9 Problems
18. a) p_elephant = 1500 kg m/s (to right)
b) |P_el/P_dart| = 625
c) P_hunter = 666 kg m/s (to right)
21. P_rain = 278,000 kg m/s
25. a) -1,500,000 N (to left)
b) -100,000 N (to left)
26. Favg = 6.7x10^6 N
29. F = 2100 N
30. a) duration of impact = 2.86x10^03 sec
b) average force = 1100 N (left)
31. p(t)= 10i + 20t j kg m/s
F(t) = dp/dt = 0i + 20j N
32. a) (i) impulse for 04 problems with no work.