Download Figure 6.27 Glancing collision for Exercises 17, 18, and 44 17. ll A

Figure 6.27 Glancing collision for Exercises 17, 18, and 44
17.
 A 0.20-kg billiard ball traveling at a speed of 15 m s strikes the side rail of a pool table at an
angle of 60° (Fig. 6.27). If the ball rebounds at the same speed and angle, what is the change in its
momentum? p  (3.0 kg  m s)yˆ
18.
 Suppose the billiard ball in Fig. 6.27 approaches the rail at a speed of 15 m s and an angle of
60°, as shown, but rebounds at a speed of 10 m s and an angle of 50°. What is the change in
momentum in this case? [Hint: Use components.] (1.1 kg  m s)xˆ  (2.6 kg  m s)yˆ
19.
 A person pushes a 10-kg box from rest and accelerates it to a speed of 4.0 m s with a constant
force. If the box is pushed for a time of 2.5 s, what force is exerted by the person? 16 N
23.
 A major league catcher catches a fastball moving at 95.0 mi h and his hand and glove recoil
10.0 cm in bringing the ball to rest. If it took 0.00470 seconds to bring the ball (with a mass of 250 g)
to rest in the glove, (a) what is the magnitude and direction of the change in momentum of the ball?
(b) Find the average force the ball exerts on the hand and glove. (a) 10.6 kg  m s opposite vo (b)
2.26  103 N
41.
 A boy catches—with bare hands and his arms rigidly extended—a 0.16-kg baseball coming
directly toward him at a speed of 25m s. He emits an audible “Ouch!” because the ball stings his
hands. He learns quickly to move his hands with the ball as he catches it. If the contact time of the
collision is increased from 3.5 ms to 8.5 ms in this way, how do the magnitudes of the average
impulse forces compare? 1.1  103 N and
42.
4.7  10 2 N
 A one-dimensional impulse force acts on a 3.0-kg object as diagrammed in \/Fig. 6.29. Find (a)
the magnitude of the impulse given to the object, (b) the magnitude of the average force, and (c) the
5.5 102 N
32 m s
final speed if the object had an initial speed of 6.0 m s. (a) 77 N  s (b)
(c)
61.
 Two identical cars hit each other and lock bumpers. In each of the following cases, what are the
speeds of the cars immediately after coupling bumpers? (a) A car moving with a speed of 90 km h
approaches a stationary car; (b) two cars approach each other with speeds of 90 km h and
120 km h , respectively; (c) two cars travel in the same direction with speeds of 90 km h and
15 km h (c) 105 km h
120 km h , respectively. (a) 45 km h (b)
82.
 A 4.0-kg ball with a velocity of 4.0 m s in the  x-direction collides head-on elastically with a
stationary
2.0-kg
ball.
What
are
the
velocities
of
the
balls
after
the
collision? v1  1.3 m s; v2  5.3 m s
78.
CQ Discuss the common and different characteristics of an elastic collision and an inelastic
collision. How can you prove a collision is elastic?
1.
Find the final velocity of the 3 kg chunk after the explosion. (7 points)
v
5 kg
10 m/s
3 kg
5 kg
3 kg
2 kg
vi = 0
2 kg
20 m/s
1.
Given a two dimensional elastic collision between two masses shown below, find the final
velocity (magnitude and direction) of the 10 kg mass. The 7 kg mass is deflected 25 from its
original path. (8 points)
7 kg
3 m/s
7 kg
25
5 m/s
10 kg
?
v= 0
v?
10 kg