Forces
What is a force?
A push or a pull on an object that can change its state of motion.
What is motion?
A change in an object's position.
Question: The acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its what?
Mass.
Question: What does Newton's Third Law state about action and reaction forces
Question: Why does a magician pull a tablecloth out from under a dinner setting without the dishes moving?
he inertia of the dishes keeps them at rest. The quick pull of the cloth is too fast to apply a significant unbalanced force to them.
What is the force that pulls objects toward the center of the Earth?
Gravity.
What is the difference between speed and velocity?
Velocity is speed in a specific direction.
Question: If you apply the same force to two objects of different masses, which object will have a greater acceleration?
When you push on a wall, what is the reaction force?
The wall pushes back on you with an equal and opposite force.
Question: What is the concept that explains why an asteroid can travel through space for millions of years without an engine?
n object in motion stays in motion with constant velocity because there are no unbalanced forces like friction or air resistance in space.
What is the unit used to measure force?
What is the rate at which velocity changes?
Acceleration.
Question: To calculate the net force on an object, you must account for all of the what?
Forces acting on the object.
uestion: Why do action and reaction forces not cancel each other out?
They act on two different objects.
What is the reason you should use a seatbelt in a car?
In a crash, a seatbelt provides the unbalanced force needed to stop your body from continuing to move forward due to inertia.
What two factors does the strength of the force of friction depend on?
The types of surfaces and how hard the surfaces are pushed together.
What two things are needed to describe an object's motion?
Speed and direction.
Question: How does an object's acceleration change if you apply the same force to it, but its mass is doubled?
Its acceleration will be halved.
: When a rocket launches, what is the action force and what is the reaction force?
Why does a baseball player "follow through" with a swing to hit a home run?
Following through extends the time the bat is in contact with the ball, increasing the impulse and applying a greater final force to the ball.
What causes a change in motion
An unbalanced force.
uestion: According to this law, the forces of action and reaction are always what?
Equal in magnitude and opposite in direction.
Question: If two objects are pushed with the same force, which one will have the greater acceleration?
The object with the smaller mass.
Why does a baseball bat hitting a ball cause a large acceleration for the ball but a negligible acceleration for the bat?
The force on both the bat and the ball is equal, but the ball has a much smaller mass, resulting in a much larger acceleration.
A bowling ball and a tennis ball are rolled down the same ramp. Which one requires more force to stop it?
The bowling ball, because it has more mass and therefore requires a larger force to achieve the same deceleration