Forces
What is the difference between balanced and unbalanced forces?
Balanced forces = all forces are equal, no change in movement
Unbalanced forces = forces are unequal, change in movement
What does it mean to describe a car's motion as "40 mph towards the south"? (Question 7 on your worksheet)
You are describing velocity
State Newton's First Law of Motion.
Inertia: Object at rest stays at rest, or object in motion stays in motion, unless acted upon by an outside force.
Which of the following is NOT an example of potential energy: a battery, a speeding bullet, or a stretched rubber band?
A speeding bullet
What will happen to an object if a force acting on it stops and no other force acts on it?
It will keep moving in the same direction. (Inertia)
What diagram do we use in order to show forces acting on an object?
Force diagram
Write whether the following is acceleration, deceleration, or no acceleration: "A bus turns at a constant speed."
no acceleration
Suppose you were to fill a balloon with air then let go of it without tying it closed. What would cause the balloon to fly away?
The balloon's movement is the reaction to the force of air escaping.
Describe the difference between kinetic and potential energy using examples.
Potential: stored energy, ex: lifting object up, pulling back an arrow on a bow
Kinetic: energy of object in motion, ex: falling object, arrow being released from bow and flying
How can you determine if an object is in motion?
can see or feel it, use a frame of reference to compare
In the absence of friction, how will three different forces acting on a box affect its motion? (Question 9 on your worksheet)
The forces will cause the box to move to the left.
What is the relationship between speed and velocity?
Velocity = speed plus direction
What does Newton's Third Law of Motion state?
Explain what happens to the potential energy of a rock as it falls off a cliff.
Potential energy decreases as kinetic energy increases.
If an object is moving at a constant speed and a force pushes it in the same direction, what will happen to the object?
The object will accelerate.
Explain how gravity affects objects in motion.
pulls objects down towards earth
Explain how acceleration can occur even if an object's speed is constant.
It cannot occur with constant speed. The object would have to speed up or slow down.
If a model boat experiences an acceleration of $3.0 , m/s squared, what other information do you need to determine the force acting on it?
Mass
Complete this statement: "When a skier rides a ski lift uphill, ____ energy is stored. As the skier goes downhill, this energy converts to ____ energy." (part of Question 8 on your worksheet)
potential, kinetic
In which scenarios is acceleration occurring? (Question 6 from worksheet, list out letters of scenarios)
a and c
Describe a scenario where friction is beneficial.
stopping a car
Calculate the acceleration of a car that slows down from 20 m/s to 10 m/s in 5 seconds?
How would you apply Newton's laws to explain why a passenger lurches forward in a car that suddenly stops?
Inertia: person wants keeps moving forward but car stopping is an outside force
How does kinetic energy change when an object accelerates? (Hint: KE = (mv2)/2 and acceleration is increase in velocity)
Kinetic energy increases
Jen and Alex are sitting opposite each other on a ride that is moving clockwise at a constant speed. Jen tosses a piece of candy to Alex. From Alex’s point of view, where will the candy land?
On his right