Vocabulary
How far an object goes in a certain amount of time.
speed
Give an example of speed (units included)
Answers vary
55mph
70km/h
5m/s
If you are sitting in a chair, are you moving according to this classroom? Explain
If you are standing in this classroom are you moving according to Earth? Explain
No. The room is not moving and you are in the classroom
Yes. The Earth is moving (spinning on it's axis and moving around the sun)
If car A has a mass of 250g moving at 8km/h and car B has a mass of 700g 8km/h
Which car will do more damage? Explain
CarA
KE=0.5*250*8*8=8000
Car B
KE=0.5*700*8*8=22400
Ball B will do more damage because it's bigger and both cars are going the same speed
What type of energy does Friction create?
Thermal (heat)
Speed (Magnitude) & Direction
Velocity
Give an example of velocity (unit included)
Answers Vary
A car driving 55mph North
What is friction? What direction does friction act on an object
The resistance on an object
Friction works in the opposite direction of friction
Car A has a mass of 100g and is traveling at a speed of 150km/h
Car B has a mass of 250g and is traveling as a speed of 50km/h.
Which car will do more damage
Car A
KE=0.5*100*150*150=1,125,00
Car B
KE=0.5*250*50*50=312,500
Car A will do more damage.
If a car is already moving at 20km/h and the friction force and applied forces are the same, what will happen to the car?
It will continue to move at 20 km/h. The forces are equal
F(net)=0 forces are balanced.
What are 3 ways to accelerate?
change direction, change speed, change speed & direction
speed up, slow down, change direction
Give an example of an object accelerating.
You can draw a label a picture or use words to explain
Answers Vary
A ball falling on the floor and bouncing up
A car turning left
If you push an object down a ramp slowly, which ramp surface should you use? Explain
Sidewalk ramp
Wooden ramp
Sidewalk. It is a rougher surface
According to the data below:
What is the relationship between speed and stopping distance?
Speed: Distance to stop
2.0m/s 10m
2.5m/s 12m
3.0m/s 17m
3.5.0m/s 22m
4.0m/s 30m
when the speed is 2x the stopping distance is 3x
You are driving a car at a constant speed of 70mph. What happens to your distance traveled if you double your time?
Hours Miles
1 70
2 140
3 210
4 280
When the time doubles the miles driven also doubles
1 to 2 hours 70x2=140 miles
2 to 4 hours 140x2=280 miles
A push or pull
Force
Look at the equation for kinetic energy, which factor has a greater impact on kinetic energy? explain
KE=0.5*m*v*v
velocity. Velocity is multiplied 2x while mass is multiplied 1x
What is a frame of reference
a point of view that is used to describe the motion of an object
Write down what type of accelerating is happening.
Answers vary
Speeding up, slowing doing, changing directions
Both change in speed and direction
What happens to the kinetic energy when the speed is doubled
Speed (km/h) Kinetic Energy (J)
10 20
15 40
20 60
25 40
When the speed doubles the Kinetic energy triples (3x)
Kinetic, Potential, Nuclear, Gravitational, Chemical, Elastic
When 2 objects collide what happens to the kinetic energy. Which object will move more? (calculate the net force with the direction)
Object 1: Mass 50g with a force of 100N to the right
Object 2: Mass 170g with a force of 100N to the left
Object 1 will move more.
Net Force: 170-50=120 to the right
Explain/Describe what the 2 frames of references for the ice cream in the following set up
A person is on the sidewalk and see a kid eaitng an ice cream in a car
According to the person on the side walk the ice cream is moving b/c the car is moving
According to the kid holding the ice cream, the ice cream is not moving b/c the kid is with the ice cream
If you are in class, explain 2 points of refereces.
1. When are you considered moving
2. When are you not considered moving
1. If the reference point is the sun or object in space
2. If the reference point is in the classroom
If the mass triples (3x) what happens to the Kinetic energy
Mass (g). Kinetic Energy (J)
5 30
10 45
15 60
20 95
mass 5 to 15
kinetic energy 30 to 60