Motion Diagrams & Vocab
An object we can use to tell the motion of another object
Reference Point
What is the equation we use to calculate SPEED?
Speed = Distance / Time
What is the definition of Newton's 1st Law?
An object in motion or at rest will remain that way unless acted on by an outside force.
What is Newton's 2nd Law? State it in both words and in the formula.
F = ma OR the net force on an object is equal to the object's mass * acceleration
What is Newton's 3rd Law?
For every action, there is an equal and opposite reaction.
The _________ and __________ are key characteristics that define VELOCITY
Speed and Direction
A vector describes ________ and _________
Magnitude and Direction
What is 'inertia'? What property of an object does it rely on?
An object's natural ability to resist changes in motion. Relies on an object's mass.
Calculate the force needed to pull a 200kg cart at an acceleration of 2.5m/s/s. Don't forget the units your answer should be in!
F = 200kg * 2.5m/s/s = 500N
What is a force? Provide an example of ONE type of force we have talked about so far.
A force is anything that can push or pull another object
Examples: gravity, friction, air resistance, normal, weight, tension
Define acceleration and provide an example.
Acceleration: the rate in change of velocity
Examples could include: throwing a ball from rest, riding on a rollercoaster, launching a rocket, etc.
Calculate the speed (WITH UNITS) of a soccer ball that travels 25 meters in 15 seconds
25/15 = 1.67m/s
What can cause an object that is not currently in motion to begin moving?
Forces (push or pull)
Using Newton's 2nd Law, explain how a rocket is capable of liftoff using jet propulsion. You should include force, mass and acceleration in your answer.
The force of the thrusters eventually overcomes the mass of the rocket, and allows the rocket to accelerate into the air
If an object is in motion, what does this say about the forces acting on that object?
The forces are unbalanced
In a position vs time graph, what variable ALWAYS goes on the X-Axis? What variable ALWAYS goes on the Y-Axis? Provide units for both.
X-Axis = Time (seconds)
Y-Axis = Position (meters)
I launch a cannonball 12.5m away and find that the speed is 5.4m/s. How long did it take my cannonball to travel 12.5m?
T = 12.5m/5.4m/s = 2.3s
What kind of forces cause an object to stop moving on our planet? List three.
1.) Gravity
2.) Friction
3.) Air resistance
4.) Weight
If the cart of a rollercoaster weighs 220kg, and the force pulling the cart is 1200N, what is the acceleration of the cart? Use correct units!
a = 1200N/220kg = 5.45m/s/s
Any CONTACT FORCE always has this type of force pushing back on it:
Normal Force
Using the example on the white board:
What is the acceleration doing at Point A?
What happens at Point B?
What is the acceleration doing at Point C?
Point A: Acceleration increases
Point B: Velocity is constant
Point C: Acceleration decreases
1km = 1000 meters
1 hour = 60 minutes = ???? seconds
25km = 25,000m
4 hours = 3600(4) = 14,400s
25,000m/14,400s = 1.73m/s
In terms of forces, what is friction?
Friction is a resistance force that causes motion to be lost
Mr. Breeden's son weighs 42lbs and likes to launch himself down slides. If he races down a slide at 5ft/s/s, what force does he launch himself with?
1lb = .45kg
1ft = .304m
42lb = 18.9kg
5ft = 1.65m
F = 18.9kg*1.65m/s/s = 31.185N
A = normal force
B = weight/gravity force
C = pull/contact force
D = friction
UNBALANCED because box is moving.