Friction and Gravity
True or false: Friction is a force of two objects that push against each other.
What is true?
Which of Newton's Laws relates the force needed to move an object with the mass of the object and it's acceleration?
What is Newton's second law?
The formula for momentum
What is mass time velocity?
p = mv
Magnets have two poles. Name them.
What is north and south poles?
The two types of currents for electricity
What is AC and DC?
AC = alternating current
DC = direct current
The four types of friction:
What is sliding, rolling, fluid, and static?
The "Law of Lazy" is more formally known as _________.
What is Newton's First Law?
A car has 30,000 kg m/s of momentum when it runs into a tree. The car weighs 1500 kg. How fast was the car going when it hit the tree?
What is 20m/s?
p = mv
30,000 kg m/s = (1500kg)(v)
v = 20m/s
Magnets of the same pole _____ and magnets of opposite poles ____.
What is repel and attract?
Magnets of the same pole repel and magnets of opposite poles attract.
Provide two examples of everyday electromagnets.
*Answers will vary, sample answers below.*
Speakers, MRI machines, doorbells, motors, and appliances.
Gravity is affected by these two factors.
What is mass and distance?
Inertia is a vocabulary word related to which law?
What is Newton's First Law?
The Law of Conservation of Momentum
What is momentum is neither created nor destroyed, only transformed or transferred from one form to another?
These items are needed to make an electromagnet.
What is metal nail, copper wire, and a battery?
This device converts mechanical energy into electrical energy.
a. Generator
b. Transformer
c. Voltage
d. Current
What is a. Generator?
Which surface has the most friction for a hockey puck sliding across it?
a. grass
b. ice
c. tile
d. wood
What is a. grass?
Provide an example of Newton's First Law.
*Answers will vary, sample answer below.*
When you are riding in a car and the driver suddenly breaks, your body keeps moving forward while the car stops. Your seatbelt stops you from hitting the dashboard or window.
The momentum of a 950 kg car moving at 10.0 m/s
p = mv
p = (950kg)(10.0m/s)
p = 9,500 kg m/s
What is the purpose the Earth's magnetic field?
What is to protect us from charged particles from the sun?
Explain how a motor or generator works.
Converts electric energy to mechanical energy (electric to mechanical energy)
OR
Current moves through the armature inside a magnetic field, making armature turn.
As the distance between two objects increases, the force of gravity will _________.
What is decrease?
Kayaking requires you to use a paddle to push your boat forward. Describe which law this shows and how.
What is Newton's Third Law because the action is pushing the water backward and the reaction is the boat moving forward?
A blue car is sitting at a stoplight waiting for it to turn green. Suddenly, a red car hits the car from behind, and the blue car moves forward. Explain why this happens.
What is conservation of momentum?
Momentum is conserved (saved) and is transferred from the red car to the blue car, so the blue car now has momentum and moves forward.
What are the three reasons that electromagnets are so useful?
What is
1. they are easy to make,
2. they can be turned on and off, and
3. they are very strong?
(must get all three)
Use your own words to explain how electricity gets from power plants to our homes.