Momentum and Collisions Name: Momentum, Impulse and Momentum Change Read from Lesson 1 of the Momentum and Collisions

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Momentum and Collisions Name:

Momentum, Impulse and Momentum Change
Read from Lesson 1 of the Momentum and Collisions chapter at The Physics Classroom:
http://www.physicsclassroom.com/Class/momentum/u4l1a.cfm

http://www.physicsclassroom.com/Class/momentum/u4l1b.cfm
MOP Connection: Momentum and Collisions: sublevels 1 and 2

Momentum

1. The momentum of an object depends upon the object's ___A, D___. Pick two quantities.

a. mass - how much stuff it has

b. acceleration - the rate at which the stuff changes its velocity

c. weight - the force by which gravity attracts the stuff to Earth

d. velocity - how fast and in what direction it's stuff is moving

e. position - where the stuff is at

2. Momentum is a ___vector___ quantity.

a. scalar b. vector

3. Which are complete descriptions of the momentum of an object? Circle all that apply. __B, E__

a. 2.0 kg/s b. 7.2 kg•m/s, right c. 6.1 kg•m/s2, down

d. 4.2 m/s, east e. 1.9 kg•m/s, west f. 2.3 kg•m/s

(Proper units - kg•m/s - and a direction are required.)

4. The two quantities needed to calculate an object's momentum are __mass__ and __velocity__.

 5. Consider the mass and velocity values of Objects A and B below. Compared to Object B, Object A has _two times the_ momentum. a. two times the b. four times the c. eight times the d. the same e. one-half the f. one-fourth the g. ... impossible to tell without knowledge of the F and a. 6. Calculate the momentum value of ... . (Include appropriate units on your answers.)

a. ... a 2.0-kg brick moving through the air at 12 m/s.

p = m•v = (2.0 kg)•(12 m/s) = 24 kg•m/s
b. ... a 3.5-kg wagon moving along the sidewalk at 1.2 m/s.
p = m•v = (3.5 kg)•(1.2 m/s) = 4.2 kg•m/s
7. With what velocity must a 0.53-kg softball be moving to equal the momentum of a 0.31-kg baseball moving at 21 m/s?
psoftball = pbaseball

(0.53 kg)•vsoftball = (0.31 kg)•(21 m/s)

vsoftball = 12m/s
Impulse and Momentum Change
 8. Insert these words into the four blanks of the sentence: mass, momentum, acceleration, time, impact, weight, impulse, and force. (Not every word will be used.) In a collision, an object experiences a(n) ____force____ acting for a certain amount of _____time_____ and which is known as a(n) __impulse__ ; it serves to change the __momentum__ of the object. 9. A(n) ___impulse___ causes and is equal to a change in momentum.

a. force b. impact c. impulse d. collision

10. Calculate the impulse experienced by .... . (Show appropriate units on your answer.)

a. ... a 65.8-kg halfback encountering a force of 1025 N for 0.350 seconds.

Impulse = F•t = (1025 N)•(0.350 s) = 359 N•s
b. ... a 0.168-kg tennis ball encountering a force of 126 N that changes its velocity by 61.8 m/s.
Impulse = ∆momentum =m•∆v = (0.168 kg)•(61.8 m/s) = 10.4 kg•m/s = 10.4 N•s
11. Determine the impulse (I), momentum change (p), momentum (p) and other values.
A 7-ball collides with the 8-ball. A moving medicine ball is caught by a girl on ice skates.  A car is at rest when it experiences a forward propulsion force to set it in motion. It then experiences a second forward propulsion force to speed it up even more. Finally, it brakes to a stop. A tennis ball is at rest when it experiences a forward force to set it in motion. It then strikes a wall where it encounters a force that slows it down and finally turns it around and sends it backwards. © The Physics Classroom, 2009 Page