Transcript Final Review - BYU Physics and Astronomy

FINAL
REVIEW
JERIKA MCKEON
ANNOUNCEMENTS
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STUDY TIPS
• Look at a question conceptually first, then look to see if
your calculated answer agrees.
• Check units
• Ask “What if?” questions.
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What if there was friction?
What if I was given different values?
What if I was asked to solve for something different?
What if a given value was bigger/smaller?
PROBLEM
BREAKDOWN
• Unit 1: 10 problems (4 worked & 6 conceptual)
• 2 problems from Exam 1 that were NOT on Exam 2
• Unit 2: 7 problems (4 worked & 3 conceptual)
• 2 problems from exam 2 that WERE on Exam 3
• Unit 3: 8 problems (4 worked & 4 conceptual)
• 2 problems from Exam 3
• Post Unit 3: 8 problems (5 worked & 3 conceptual)
• 33 total problems
UNIT 1:
KINEMATICS &
FORCES
10 PROBLEMS
UNIT 1- KINEMATICS
• Basic Vocabulary
• Distance vs Displacement
• Speed vs Velocity
• Acceleration
• Scalars vs Vectors
• Instantaneous vs Average
• 1D Kinematics
• Trig
• 2D Vectors (relative velocity)
• 2D Kinematics
UNIT 1- KINEMATICS
PRACTICE PROBLEM
I drive 2 miles North to the grocery store. Then I drive 1 mile
East to the post office and then I drive home. The entire time I
travel at 45 mph.
What is my total distance traveled?
What is my total displacement traveled?
What is my instantaneous speed while I am driving to the grocery
store?
What is my instantaneous velocity while I am driving to the grocery
store?
What is my average speed for the whole trip?
What is my average velocity for the whole trip?
What is my average acceleration for the whole trip?
UNIT 1- KINEMATICS
PRACTICE PROBLEM
A bullet is shot at a 30° angle. When the bullet is rising, what
direction is it accelerating?
a) Up
b) Down
c) Not accelerating
While the bullet is falling, what direction is it accelerating?
While the bullet is at the top of its path, in what direction is it
accelerating?
UNIT 1- KINEMATICS
PRACTICE PROBLEM
A baseball is hit at an upward angle across a flat field. The
baseball is hit 1 meter above the ground and lands some
distance away.
At what part of its path does the ball have its maximum
speed?
a) Right after it leaves the batter’s hand
b) Halfway to the top
c) At the top of its path
d) Halfway from the top to the ground
e) Right before it hits the ground
f) There’s not enough information to say
At what part of its path does the ball have its minimum
speed?
UNIT 1- KINEMATICS
PRACTICE PROBLEM
A ball is shot horizontally from a table at the same time as
another ball is dropped from the same height. Which ball hits
the ground first?
a) The one shot horizontally
b) The one that was dropped
c) Same time
UNIT 1- NEWTON’S LAWS
• 1st Law: Objects have constant velocity unless acted on by
unbalanced forces
• 2nd Law: F=ma
• 3rd Law: Force Pairs
• Know how to use them in problems
UNIT 1- FORCES
• Typical Forces
• Fg=Weight
• N
• Ff
• T
• Other Stuff
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Using Kinematics
Ropes & Pulleys (2 Body Systems)
Inclined Planes
Centripetal Force
Newton’s Laws of Gravity
Impulse
UNIT 1- FORCES
PRACTICE PROBLEM
The work done by static friction is always:
a) Positive
b) Negative
c) Parallel to the surface
d) Perpendicular to the surface
e) Zero
UNIT 1- FORCES
PRACTICE PROBLEM
A toy car on a ramp is given a quick upward push. As a result
of the push, the car travels up the ramp, slows down and
stops, then rolls back down again.
As the car moves up the ramp, the net force on it is:
a) Up the ramp and increasing in magnitude
b) Up the ramp and decreasing in magnitude
c) Up the ramp and constant in magnitude
d) Down the ramp and increasing in magnitude
e) Down the ramp and decreasing in magnitude
f) Down the ramp and constant in magnitude
g) Zero
Right at the top of the car’s motion, the net force on it is ___.
As the car moves down the ramp, the net force on it is _____.
UNIT 2: ENERGY,
MOMENTUM,
ROTATION
7 PROBLEMS
UNIT 2- ENERGY, WORK,
POWER
• Work = Fd (What direction does that force have to be?)
• Types of Energy
• Translational Kinetic Energy
• Rotational Kinetic Energy
• Gravitational Potential Energy
• Spring Potential Energy
• Conservation of Energy
• When is energy conserved?
• Elastic vs Inelastic Collisions
• 1D & 2D
UNIT 2- MOMENTUM
• When is momentum conserved?
• 1D & 2D Collisions
• Multi-Step Collisions (bullet into block)
UNIT 2- MOMENTUM
Suppose a little boy is floating in outer space with no forces
acting on it. The boy is at rest, so its momentum is zero.
Suddenly, the boy pulls out a pvc pipe and blows a
marshmallow out of one end. The marshmallow goes one
way and the boy goes the other way. Was the momentum of
the “boy and marshmallow” system conserved?
a) Yes
b) no
UNIT 2- ANGULAR
KINEMATICS
• Kinematic Equations are the same as for linear kinematics
• s=θ*r (arc length)
• ω=v*r (angular velocity)
• α=a*r (angular acceleration)
UNIT 2- TORQUE
• τ = 𝑭𝒓
• Equilibrium Problems
UNIT 2- ANGULAR
MOMENTUM
• p=m*v
• L=I*ω
• Hidden angular momentum=r*p (radius has to be
perpendicular to linear momentum)
UNIT 1- KINEMATICS
PRACTICE PROBLEM
Captain America can throw his 10kg shield with a velocity of
10m/s at 30°. How far does the shield travel? Would it travel
further or not as far if the shield weighed 10kg?
UNIT 1- NEWTON’S LAWS
PRACTICE PROBLEM
If a dog weighs 30kg, what is the force of the floor on him
when he is on Earth?
What would a bathroom scale read when he is on a planet
with half of the acceleration due to gravity than Earth has?
UNIT 1- FORCES
PRACTICE PROBLEM
A force F is applied to a crate on an incline so that he crate
does not slide. The angle of the incline is 35°.
If the minimum force F that has to be applied is 35N, what is
the coefficient of friction that is needed to keep the crate
from slipping? What type of friction is it?
UNIT 1- FORCES
PRACTICE PROBLEM
Superman can kick a 2kg soccer ball at 100m/s. It takes 0.05s
for him to kick the ball. What force does he exert on the ball?
What is the ball’s acceleration?