Vocabulary
the type of force that causes an object to change its motion
an unbalanced force
Finish the phrase: "An object in motion stays in motion and...
an object at rest stays at rest unless acted on by an unbalanced force
the formula for Newton's 2nd Law
Force = Mass x Acceleration
(F=MA)
Newton's 3rd Law states that...
every action has an equal and opposite reaction
A tennis ball is served, the tennis player on the other side of the net swings at the ball but misses. Which law explains why the ball stays in motion until it hits the fence?
Newton's 1st Law
define gravity
the force that pulls objects toward Earth's center
In the following example, what is the unbalanced force?
A car is driving down the street, but comes to an abrupt stop when it hits a tree.
the tree
Write/ draw an example of Newton's 2nd law
(show)
Write / draw an example of Newton's 3rd Law.
(show dry-erase board)
Which of Newton's Laws take force into consideration?
all of them
a push or pull
force
What happens without friction?
Finish Newton's 2nd Law: Acceleration occurs when...
a force acts on a mass
A swimmer pushes off the side of the pool and is propelled forward by the force of the pool exerting a force on the swimmers foot. Explain this in terms of Newton's 3rd Law.
***DAILY DOUBLE***
the action is pushing off of the side of the pool, the the side of the pool pushes your forward
Why does a marble on the floor slow down and eventually stop rolling if Newton's 1st Law says an object in motion stays in motion?
friction
a change in velocity is
acceleration
What is another name for Newton's First Law?
law of inertia
I hit a baseball with a plastic bat then I hit the same baseball with a metal bat. Which will go farther. Why?
Metal. More mass = more force
Explain the action and reaction forces acting on a book resting on a table.
Action: Book pushes down on table
Reaction: Table pushes up on book
Safety researchers are simulating a head on collision using crash test dummies to represent what happens to people. One of the dummies doesn't have a seat belt on. What happens to the crash test dummy without the seatbelt when the car hits the concrete barrier and why?
the dummy flies out the window because an object in motion wants to stay in motion (inertia)
define inertia
an object's tendency to resist any change in its motion
Which of the following has the greatest inertia?
Person, Car, Jet, or Train
Train (more mass = more inertia)
Which would have a greater acceleration, a small car or a large car, if the same force is applied?
a small car
How are balanced forces and action-reaction forces DIFFERENT.
Both: Equal and opposite forces
Balanced: forces act on SAME object, do NOT cause change in motion
Action-Reaction: forces act on DIFFERENT objects and CAN cause a change in motion
Mrs. Devorah is going down the sidewalk on her skateboard; Ms. Hall decides to get on too. What will Mrs. Devorah have to do to keep the skateboard moving at the same velocity?
push with more force