Simple Machines
All levers have a...
Fulcrum
According to legend, what inspiring event happened to Newton one day as he sat under a tree?
An apple fell on his head.
What force causes a you to fall to the ground when you trip or lose your balance?
gravity
The action or process of changing place or position is known as ____.
motion
Your body is made up of machines. Explain what this means.
Arms/legs/jaw = levers, teeth = wedges. Your moving parts need lubrication; As you age, your parts may begin to rub together.
A machine can never have an efficiency of...
100%
Which of Newton's Laws says that every action has an opposite, but equal reaction? (Think about rockets)
Newton's 3rd Law
What force holds back the movement of a sliding object, by acting in the opposite direction of the moving object?
friction
You apply the same force to each of the following objects: Ping-pong ball, baseball, and bowling ball. Which one experiences the greatest acceleration?
The ping pong ball.
Explain why it is important to wear a seat belt when you're driving in a car.
Inertia
You put 100 newtons into a house jack. It lifts the house with a force of 20,000 newtons. What is the mechanical advantage of the machine?
MA= 200
Which of Newton's Laws explains how a kickball with a certain mass will accelerate if you apply a force to it (F=MA)?
Newton's 2nd Law
The pull of gravity on an object is called the object's ____.
weight
What is the difference between acceleration and deceleration?
Accel = speeding up, Decel = slowing down
Newton's first law of inertia says that moving objects will never ____ and objects at rest will ____.
slow down or stop, and stay at rest
An inclined plane wrapped around a central column or rod is known as what?
a screw
Which of Newton's Laws explains why you can leave your pencil on your desk this afternoon, and it will still be there tomorrow?
Newton's 1st Law
Explain why engines and other machines need lubrication.
Lubrication reduces friction, wear & tear, and is necessary with complex machines with lots of moving parts
One horse pulls a sled with 100 N to the left. Another horse pulls the same sled with 300 N to the left. What is the net force on the sled?
400 N left
All simple machines involve a tradeoff. What does this mean in terms of W=f*d?
You have to trade distance for force, or force for distance.
Which of Newton's Laws is known as the law of inertia?
Newton's 1st Law
Explain why your weight changes when you go from the Earth to the Moon.
The Moon has less gravity than the Earth, so it pulls on you less strongly. Your weight depends on the local force of gravity.
In our lever lab, how did we make it easier to lift the load of pennies?
We moved the fulcrum towards to load