Chapter 5 Science Test Flashcards
Newton's Laws
When a ball is sitting on the ground, what force(s) are acting on it?
normal force
Constant motion requires constant force. (True or False)
False
Why does a kicked soccer ball eventually slow down to a stop?
Because friction was acting on it
What does Newton’s first law state?
When the net force is zero, objects at rest stay at rest and objects in motion keep moving with the same speed and direction.
An object cannot speed up, change direction, or slow down, unless there is a ________ acting on it.
Net Force
What are balanced forces
Forces are balanced when they add up to zero net force
What are unbalanced forces
Forces are unbalanced when the net force is not exactly zero.
The first law is often called “___ __ ______.”
Law of Inertia
What is Inertia?
The property of an object that resists changes in motion.
When you hit a golf ball, the forces are the weight of the ball, normal force from the ground, and friction. Which force is causing movement?
All of the forces together! There is almost always more than one force present because gravity acts on all objects.
Remember that force is a “________!”
vector!
Newton’s first law says that a force is needed to change motion. But what kind of change happens?
the acceleration changes
What are the three main ideas related to the second law?
- Acceleration is the result of unbalanced forces.
- a larger force makes a proportionally larger acceleration.
- acceleration is inversely proportional to mass.
Newton’s second law
Any unbalanced force results in acceleration.
What does “Acceleration is proportional to force” mean?
It means that all other things are equal, if the force doubles, the acceleration also doubles.
Acceleration is always in the same “_______” as net force.
direction
the greater the mass, the “__________” the acceleration for a given force.
smaller
What does mass create?
inertia
What does mass resist?
acceleration
Forces always come in ______.
pairs
Newton’s third law
every action force creates a reaction force that is equal in strength and opposite in direction.
Forces only come in “_____ _____” pairs
“action reaction”
Action and reaction forces cancel each other out. (TRUE OR FALSE)
FALSE
More mass results in ______ acceleration.
LESS acceleration
