Week 29 Practice Problems 2013-2014
NAME________________
1. - Question Details Momentum 2D explosion 1 [1719459]
A bomb of mass 11.9 kg sits at rest at the origin. The bomb explodes (mechanically) into three pieces. One
piece (m1 = 3.74 kg) moves away with a velocity of 127 m/s @ 147°, and another piece (m2 = 4.06 kg)
moves away with a velocity of 153 m/s @ 30.2°. Assume that no mass is lost in the explosion.
A. What is the mass of the third piece?
4.10 kg
B. List the components for each momentum vector after the explosion in the table.
X Components
Y Components
P1'
259 kg m/s
-398 kg m/s
P2'
312 kg m/s
P3'
-571 kg m/s
537 kg m/s
-139 kg m/s
C. What is the momentum of the third piece in standard vector notation? 588 kg m/s @ 256°
D. What is the velocity of the third piece in standard vector notation? 143 m/s @ 256°
2. - Question Details Giancoli5 7.P.011. [10011]
A 13 g bullet traveling 221 m/s penetrates a 2.0 kg block of wood and emerges going 161 m/s. If the block
is stationary on a frictionless surface when hit, how fast does it move after the bullet emerges?
0.39m/s
3. - Question Details Giancoli5 7.P.015. [68295]
A 0.145 kg baseball pitched at 37.0 m/s is hit on a horizontal line drive straight back toward the pitcher at
52.0 m/s. If the contact time between bat and ball is 3.00 ✕ 10-3 s, calculate the average force between the
ball and bat during contact.
4300N
4. - Question Details Giancoli5 7.P.016. [10016]
A golf ball of mass 0.045 kg is hit off the tee at a speed of 48 m/s. The golf club was in contact with the
ball for 4.5 ✕ 10-3 s.
(a) Find the magnitude of the impulse imparted to the golf ball.
2.16N·s
(b) Find the magnitude of the average force exerted on the ball by the golf club.
480N
5. - Question Details Giancoli5 7.P.017. [10017]
Figure 7-29.
A tennis ball of mass m = 0.065 kg and speed v = 55 m/s strikes a wall at a 45° angle and
rebounds with the same speed at 45° (Fig. 7-29). What is the impulse given to the wall?
5.06N·s
Magnitude
Direction ?
in the direction of the ball's original motion
opposite the direction of the ball's original motion
normal and away from the wall
normal and into the wall
****
in the direction of the ball's final motion
opposite the direction of the ball's final motion
6. - Question Details Giancoli5 7.P.018. [10018]
A 115 kg fullback is running at 3.9 m/s to the east and is stopped in 0.75 s by a head-on tackle by a tackler
running due west.
(a) Calculate the original momentum of the fullback.
Magnitude
449 kg·m/s
Direction
east
***
(b) Calculate the impulse exerted on the fullback.
Magnitude
449 kg·m/s
Direction
west **
(c) Calculate the impulse exerted on the tackler.
Magnitude
449 kg·m/s
Direction
east **
(d) Calculate the average force exerted on the tackler.
Magnitude
Direction
598N
east
**
7. - Question Details Giancoli5 7.P.021. [10021]
A ball of mass 0.340 kg moving east (+x direction) with a speed of 3.60 m/s collides head-on with a 0.460
kg ball at rest. If the collision is perfectly elastic, what will be the speed and direction of each ball after the
collision?
ball originally at rest
direction
speed
3.06 m/s
east **
ball originally moving east
Direction
west **
speed
0.54m/s
8. - Question Details Giancoli5 7.P.025. [10025]
A softball of mass 0.220 kg that is moving with a speed of 6.5 m/s (in the positive direction) collides headon and elastically with another ball initially at rest. Afterward it is found that the incoming ball has bounced
backward with a speed of 4.6 m/s.
(a) Calculate the velocity of the target ball after the collision.
1.9 m/s
(b) Calculate the mass of the target ball.
1.29kg
9. - Question Details Giancoli5 7.P.074. [10074]
A block of mass m = 2.20 kg slides down a 30.0° incline which is 3.60 m high. At the bottom, it strikes a
block of mass M = 7.40 kg which is at rest on a horizontal surface, Fig. 7-41. (Assume a smooth transition
at the bottom of the incline, an elastic collision, and ignore friction.)
Figure 7-41.
(a) Determine the speeds of the two blocks after the collision.
lighter block
4.55m/s
heavier block
3.85m/s
(b) Determine how far back up the incline the smaller mass will go.
2.11m