Name:___________________________
Quiz Act #’s 73- 81 Study Guide
Activity #74-Measuring Speed
1.) What is the definition of speed?
How much distance an object covers in a certain amount of time.
2.) How did we determine the speed of the cart as they traveled down the ramp?
We timed how long it took the car to go a certain distance and divided distance/time.
Activity #75-Interpreting Motion Graphs
1.) What does the slope of a line in a motion graph tell us?
The speed
2.) True/False and EXPLAIN. A downward slope back toward the origin represents an object
slowing down.
False, this just means the object is headed back toward the origin or starting point.
The graph to the right represents a typical
Sunday afternoon when Mr. Strelick’s front
door gets opened. The three animals all run out
the door and go different speeds and
directions.
3.) Who’s traveling at the fastest speed and
how could you tell?
Milo, because he is the coolest! (or
because his line has the steepest slope)
4.) Who came back home and how could you tell?
Serafina because she is daddy’s favorite (or because the line was pointed down)
5.) What was Serafina’s speed the first 5 second of her trip? Hint- distance/time.
1 m/s
6.) Which one was accelerating and how could you tell?
The mouse, because the line was curved indicating there was not a constant speed
and that there was a “change in speed”
Activity #76 & 77-Speed and Collisions/Mass and Collisions
1.) How did you quantify the force in these activities?
We measured how far the block moved
Activity #78-Force, Acceleration, and Mass
1.) Complete the following table
Term
Unit
Term
2 Force
Acceleration
Velocity
m/s
m/s
Mass
Unit
Newton
kg
2.) What is the equation for force?
Force= Mass • Acceleration (F= M•A)
Activity #79-Inertia Around a Curve
1.) Define Inertia
An objects resistance to change or an object in motion will stay in motion (or at rest)
2.) What cat has more inertia and explain.
Serefina, who weighs 10 pounds and is running at a speed of 5 m/s or
Milo, who weighs 13 pounds and is sleeping on the kitchen counter. (yes he does do this)
Milo because he has more mass and thus more resistance to change
3.) What is required to get an object to either stop moving, or start moving (change its motion)?
A force
4.) Why did the ball go straight out of the circular track when it reached the opening? Why did
it not continue in a circle?
It no longer had the force of the track pushing it in, so it followed
its inertia and went in a straight line.
Activity #80-Newton’s
Laws of Motion
1.) True or False- EXPLAIN- a force is required to keep an object in motion.
False, an object in motion will stay in motion
2.) True or False- EXPLAIN The lighter the object, the more force needed to stop it.
False, the lighter the object, the less inertia, therefore the less resistance
to a change in motion (stopping)
3.) Label and describe the action force and reaction forces in the picture below
Action Force- Ball applying a force to the pin
Reaction Force - Pin applying a force back to the ball
4.) In the example above why does the pin move backward and the ball continues to move
forward if both are experiencing equal forces?The
pin has much less mass
Activity #81-The Net Force Challenge
1.) If a car is parked and not moving, then the forces acting on the car must be
a.) balanced
b.) unbalanced
c.) both
2.) If a car is traveling at a constant speed, then the forces acting on the car must be
a.) balanced
b.) unbalanced
c.) both
3.) If a car is accelerating, then the forces acting on the car must be
a.) balanced
b.) unbalanced c.) both
Use the following information for questions #4-5
Serefina and Milo are both fighting over their favorite cat toy (a stuffed mouse).
Milo pulls on the mouse towards the left with a force of 12 Newtons and Serafina pulls on the
mouse with a force of 18 Newtons to the right
4.) Draw a force diagram that shows all the forces acting on the mouse.
5.) Draw a “Net Force Diagram” that only shows the “Net Force” on the mouse.
6.) How can you tell if the forces acting on an object are balanced or unbalanced?
Look to see if the object is accelerating (or changing velocity, or experiencing a change in
motion) (speeding up, slowing down or turning)
Overall Motion- The
following questions relate to multiple activities
1.) Which has more acceleration and explain why.
A snake slithering at a constant speed of 2m/s or
A giraffe galloping at a speed of 10m/s then slowing to a speed of 4m/s
Why- because it is changing speeds which is the definition for an acceleration
2.) If you apply 25 Newtons of force down onto your chair, how many Newtons of force does
your chair apply back to you and in what direction?
25 Newtons in the upaward direction
3.) A car is going around a circular track at a constant 15m/s.
Is the car experiencing a change in speed? Explain
NO, because the speed remains 15m/s
Is the car experiencing a change in velocity? Explain
Yes, the velocity is changing because the direction is changing. Velocity
is speed and direction
Is the car experiencing an acceleration? Explain
Yes, since it is changing velocity, it must be accelerating. The
definition of acceleration is anything that is changing velocity
4.) Something experiencing a BALANCED force is also experiencing a (circle all that apply)
a.) An acceleration
b.) change in velocity
c.) change in motion
d.) constant speed
5.) Something experiencing a UNBALANCED force is also experiencing a (circle all that apply)
a.) An acceleration b.) change in velocity
c.) change in motion d.) constant speed
6.) True/false and explain- if an object is moving, it must be experiencing a change in motion?
False, an object could be moving at a constant speed which does not
represent a change in motion.
7.) Which has more of a change in motion and explain why.
A car speeding up from 15m/s to 30 m/s or
A car slowing from 25m/s to 5m/s.
Because it has a “change in speed” of 20m/s where the first car has a change in speed of
15m/s. A “change in speed” (speeding up or slowing down) is a change in motion
8.) Explain how objects on earth do not “violate” Newton’s Law of Inertia? Why don’t objects in
motion stay in motion on earth?
Objects do not stay in motion because they are acted on by the forces of
gravity and friction.
9.) How does mass differ from weight?
Mass is the same no matter what and weight is how much that mass is pulled
towards the surface, which depends on gravity
10.) True/false and explain- Is an object falling at terminal velocity accelerating?
No since is traveling at a constant speed and in a constant direction (down)
11.) Two bunnies collide with an large egg. Which one collided with the egg with more
force? And why
A 10 kg bunny traveling at a speed of 100cm/second
A 8 kg bunny traveling at a speed of 6000cm/minute
WHY- 6000cm/minute is the same as 100cm.second (second vs minute). They are both
moving at the same speed, thus the more massive one must have the greater force
Mix-up Math
All Activities- Show work for all problems
Suggestion- Write what you know first, then determine what equation to use
***Watch out for the units, in some problems you will need to convert minsec or mcm or vise versa. ***
1.) What is a cars speed if it travels 30m in 1.5 seconds?
Speed=?
Distance= 30m
Time= 1.5 secs
Speed= 20 m/s
2.) How long (in hours) would it take to travel 400 miles at a speed of 65MPH
Speed= 65 MPH
Distance= 400 miles
Time= ?
Time= 6.15 hours
3.) After an afternoon of chasing his sister around the neighborhood, Milo runs home. The last
2 minutes of his trip he starts to get very tired and goes from 5 m/s to 1 m/s. What is Milo’s
acceleration the last 2 minutes of his trip?
Change in Velocity=
5m/s - 1m/s= 4m/s
Time= 2 mins = 120 s
Acceleration= change in vel.
Acceleration= 4m/s
120 s
Time
Acceleration=
-0.03 m/s2
4.) If a race car was going at a speed of 30m/s and speed up to 50m/s over 4 seconds, what
would it’s acceleration be?
Acceleration=?
Change in Velocity= 20m/s
Time= 4 seconds
Accel.= change in vel.
Accel. = 20m/s
4s
Time
Acceleration=
5 m/s2
5.) What is the momentum of a football player if they are traveling at a velocity of 9m/s and
have a mass of 150kg
Momentum= ?
Mass= 150 kg
Velocity= 9 m/s
Momentum=Mass•velocity
Momentum= 150kg • 9 m/s
Momentum=
1350 kg•m/s
6.) What is the force of the above football (mass 150kg) player when it collides with another
player with an acceleration of 5 m/s2
Force= ?
Mass= 150 kg
Acceleration= 5 m/s2
Force= mass • acceleration
Force= 150kg • 5 m/s2
Force=
750 N
7.) What would the force of a bowling ball be on a pin if the ball had a mass of 4.5kg and was traveling
at a speed of 5m/s when it collided and slowed down to a speed of 1m/s in a time of 0.5 seconds.
Since we’re trying to find the force, using the equation f=m•a and are given the “m”, we need to
fist find the “a”
Acceleration=?
Change in Velocity= 4m/s
Time= 0.5 seconds
Accel.= change in vel.
Accel. = 4m/s
Time
Than find the force…. F=M•A (see next page)
0.5s
Acceleration=
8 m/s2
Force= ?
Mass= 4.5 kg
Acceleration= 8 m/s2
Force=
mass • accel.
Force= 4.5kg • 8m/s2
Force= 36N
Formulas:
Speed= Distance
Time
Force = Mass • Acceleration
Acceleration= Change in Velocity(speed)
Time
Momentum(p)= Mass • Velocity