Question

25.) Suppose you are traveling in a bus at highway speed on a nice summer day and the momentum of an unlucky bug is suddenly changed as it splatters onto the front window. a) Compared to the force that acts on the bug, how much force acts on the bus. (more) (the same) (less)

b) Although the momentum of the bus is very large compared to the momentum of the bug, the change in momentum of the bus compared to the change in momentum of the bug is (more) (the same) (less)

c) Which experiences the greater acceleration (HINT: think of Newton’s 2nd Law)? (bus) (both the same) (bug)

d) Which, therefore, suffers the greater damage? (bus) (both the same) (the bug of course!)

II. Conservation of Momentum (Types of Collision)

Determine what type of collision are the following problems and solve.(Show your solutions)

1. A 2.50 kg ball moving at 7.50 m/s is caught by a 70.0 kg man while the man is standing on ice. How fast will the man / ball combination be moving after the ball is caught by the man?

2. A 1200 kg car traveling North at 20.0 m/s collides with a 1400 kg car traveling South at 22.0 m/s. The two cars collide and entangle. What is the resulting velocity of the wreckage?

3. A 5.00 kg ball hits a 75.0 kg man standing at rest on ice. The man catches the ball. How fast does the ball need to be moving in order to send the man off at a speed of 3.00 m/s?

4. A 1.50 x 10³ kg car traveling at 100 km/h South collides with a 1.20 x 10³ kg car traveling North at 100 km/h. The heavier car continues to move South after the collision, but slows to 25.0 km/h (convert to m/s). How fast is the lighter car moving after the collision?

5. A 1000 kg car traveling South at 20.0 m/s collides with a 1200 kg car traveling East at 20.0 m/s. The two vehicles entangle after the collision and head off as one. What is the velocity of the combined wreckage immediately after the collision?

6. A 1500 kg car traveling West at 90.0 km/h collides with a 1400 kg truck traveling North at 72.0 km/h. The two vehicles entangle after the collision and head off as one. What is the velocity of the wreckage immediately after the collision?

7. A 4.00 kg ball traveling North with a momentum of 11.2 kg.m/s collides with a 6.0 kg ball traveling West with a momentum of 18 kg.m/s. The two balls stick together and head off as one. What is the momentum of the combined masses? What is the velocity of the combined masses?

8. A 400 kg bomb sitting at rest on a table explodes into three pieces. A 150 kg piece moves off to the East with a velocity of 150 m/s. A 100 kg piece moves off with a velocity of 200 m/s. What is the velocity of the third piece?

9. A 75.0 kg man is standing at rest on ice while holding a 4.00 kg ball. If the man throws the ball at a velocity of 3.50 m/s forward, what will his resulting velocity be?

10. A person holding a 15.0 kg gun containing one 50.0 g bullet is riding on a train that is traveling at 75.0 km/h East. If the man fires the gun and the bullet moves with a velocity of 350 m/s East (relative to the train), what is the velocity of the gun relative to the ground?

Answer 1

Answer:

(22) Given, mass of the steel ball m = 2.0 kg and speed v = 2.8 m/s then the momentum of the ball is p = mv

therefore, p = (2.0 kg) (2.8 m/s) = 5.6 kg.m/s

(23) Given. velocity v = 1.5 m/s and momenyum p = 0.10 kg.m/s then mass m = p/v = (0.10 kg.m/s)/ (1.5 m/s)

m = 0.067 kg.

(24) Given, mass of the ship m = 4.23 x 108 kg and its momentum p = 4.9 x 109 kg.m/s then its speed is v = p / m

therefore, v = (4.9 x 109 kg.m/s) / (4.23 x 108 kg) = 11.59 m/s.

(25) (a) less

(b) less

(c) bug

(d) the bug of course!