Target Set 4 WITH EXAMPLES – Momentum and Impulse
4.1
I can list the factors that affect momentum and recall correct units for measuring it.
Example Problems:
What is one way to define momentum?( inertia in motion, mass * velocity)
What has more momentum: a Volkswagen Beetle going 55 mph or a fully-loaded Mac dump truck going 55
mph?(Ans: The Mac dump truck has more momentum because of its larger mass.)
True/False: An object that is stationary has momentum. (False)
True/False: An object that is more massive than another object will always have more momentum? (False, the
less massive object may just be traveling much faster than the more massive object).
What factor(s) affect the amount of momentum that an object has? (Mass AND Velocity)
Which of the following is the correct unit of measurement for Momentum?
N sec; N m/s; kg m/s; kg m/s2; kg m/s/s; N m
(Ans. kg m/s and N s)
4.2
I can explain why momentum is a vector.
Momentum is a vector because: (Ans. velocity has direction)
True/False: Mass is a vector. (False, mass is a scalar quantity)
True/False: Velocity is a vector. (True, velocity needs direction)
4.3
I can manipulate the p = mv equation to solve for any variable.
A 5 kg bowling ball travels down the lane at 3 m/s. What is its momentum? (15kg m/s)
A 40 kg student runs at 5m/s to the right. Her momentum is __________. (200kg m/s)
A 50 kg student runs at 4 m/s to the left. His momentum is ___________. (-200kg m/s)
True/False: The two students above have the SAME momentum as one another. (False, they have the same
magnitude but differ in direction of the momentum)
A ball is traveling at 6 m/s and has 42 kgm/s of momentum, what is its mass? _____ (7kg)
A boy has -45 kgm/s of momentum and masses 30 kg. What is his velocity? _____ (-1.5 m/s or 1.5 m/s, left)
4.4
I can define impulse and list its units of measurement.
The product of Force times Time is equal to ___________. (The impulse acting on the object)
When I multiply a Force x Time, the units of measurement are _________. (N s, which is the same as the
kg*m/s)
Which has a greater impulse: Object #1 that has a 1000 N force act for 15 seconds or object #2 that has a 100
N force act for 40 seconds? (Ans: Object #2)
True/False: All impulses are the same. (False, impulse is the result of Force AND the time in which the force
acts, so they are not always the same at all)
4.5
I can manipulate the Ft=Impulse equation to solve for any variable. (Level 3: Applying)
A force of 25 N acts on a ball for .2 seconds. What impulse does the ball receive? (5 N s)
A 100 N force acts on the ball for .1 seconds. What impulse does the ball receive? (10 N s)
A 10 N force acts for ¼ of a minute. What impulse does the object receive? (150 N s)
A ball receives and impulse of 50 N s when pushed with a 5 N force. How long did the force push the ball?
(10seconds)
A ball receives -30 Ns of impulse when pushed for 6 seconds. What force acted on the ball? (-5N)
4.6
I can identify that the impulse must equal the change in momentum. (Level 2:
Understanding)
If Impulse is F x t, and F x t = the change in momentum then: True/False: Impulse = the change in
momentum? (True)
The units of measurement for Impulse are N s; True/False: The N s is equal to that of a kg m/s which is says
that Impulse = Change in Momentum. (True, a N s is the same as kg m/s and Impulse IS equal to the Change in
Momentum)
Complete: An object that receives the greatest Impulse… (Ans: Receives the greatest Change in Momentum)
A 1000kg car receives an impulse of -5N s. What is its change in momentum? (-5 kg m/s)
4.7
I can manipulate the Ft = mv equation to solve for any variable.
A 10 N force pushes a 0.5 kg box for .5 seconds. What is the change in velocity of the box? (10m/s)
A 3.5 N force pushes an object for .2 seconds from 0 to 2m/s. What is the mass of the object? (.35kg)
How much force is needed to speed up a 90kg person from 2m/s to 8m/s in 0.5 a second? (1080N)
4.8
I can use impulse, change in momentum and action-reaction to explain an everyday
physical phenomenon. PLEASE SEE THE NUMEROUS EXAMPLES ON YELLOW
SHEET.
4.9
I can explain an everyday phenomenon using the law of conservation of momentum. (Level
2: Understanding)
True/False: Momentum is ALWAYS conserved? (True)
Total momentum BEFORE a collision __________ equal to the total momentum AFTER the collision. (is
ALWAYS)
Before a collision, Car #1 with a momentum of 22kg m/s hits Car #2 that has a momentum of 4kg m/s. After the
collision, Car #1 has a momentum of 18kg m/s. What is the momentum of Car #2? (Ans: 8kg m/s)
4.10
I can manipulate pbefore = pafter to solve for any variable.
Car A (mass of 1000kg) is stopped at a stoplight before it is collided with Car B (mass of 2000kg) that is
traveling at 4m/s to the right just before the collision. After the collision, Car B is traveling at 1m/s to the
right, what is the velocity of Car B AFTER the collision? ( 6 m/s to the right))
Two high schoolers are on stationary scooters. Student #1 has a mass of 85kg and Student #2 a mass of 68kg.
They push off each other. Student #1 travels to the right with a velocity of 1.4m/s. What is the velocity of
Student #2? (Ans: -1.8m/s)
Two railroad cars collide. Car #1 has a mass of 1200kg and is traveling to the right at 5m/s. Car #2 is twice
as massive and travels to the left at 3m/s. After the collision, the cars stick together. What is the velocity of the
railroad cars AFTER the collision? (Ans: -.3m/s, or .3m/s to the left)