Vocabulary
A push or a pull that can change an object’s motion.
Force
When a swimmer pushes backward on the wall of a pool, the wall pushes the swimmer forward into the water.
Newton's Third Law
What magnitude of force is required to move a 5 kg object with an acceleration of 3 m/s2?
F= 15 N
A force that opposes motion between two surfaces that are touching.
Friction
Forces acting on an object that are equal in size and opposite in direction, resulting in no change in motion.
Balanced Forces
This is an object’s tendency to resist changes in its motion.
Inertia
A soccer ball sits still on the field. It does not move until a player kicks it. Once kicked, it rolls across the grass until friction slows it down and stops it.
Newton's First Law
A net force of 20 N acts on a 5 kg object. What is the object’s acceleration?
a = 4 m/s2
This is the force of gravity acting on an object’s mass.
Weight
A 10 kg object accelerates at 2 m/s² to the right. What is the net force on the object?
20 N to the right
The attractive force between two masses; on Earth, this force pulls objects toward the center of the planet.
Gravity
An empty grocery cart is easy to push, but when it is filled with heavy food, you must push much harder to make it accelerate at the same rate.
Newton's Second Law
A force of 24 N causes an object to accelerate at 4 m/s². What is the mass of the object?
m= 6 kg
A force that is exerted on an object by a person or another object through a push or pull.
Applied Force
A box is pushed to the left with 12 N of force. Friction pushes to the right with 5 N. The upward normal force and downward gravitational force are equal.
7 N to the left
This is the rate at which velocity is changing, often measured in m/s2
Acceleration
A baseball player hits a ball. When the bat applies a greater force, the ball accelerates faster and travels farther.
Newton's Second Law
An object with a mass of 3 kg experiences a net force of 18 N. What is its acceleration?
a=6 m/s2
The support force exerted by a surface that acts perpendicular to the surface and prevents objects from falling through it.
Normal Force
A book rests on a table. The gravitational force pulling down is 15 N, and the normal force pushing up is 15 N. There are no horizontal forces. What is the net force acting on the book?
Zero
This is the metric unit of force, as defined by the amount of force needed to move 1 kg of matter at a rate of 1m/s2.
Newton
A car suddenly stops at a red light. The passengers lurch forward in their seats until the seatbelt pulls them back.
Newton's First Law
Bailey's dog Bluey weighs 98 N here on Earth; what is this dog's mass?
m= 10 kg
Free Body Diagrams are used to evaluate all of the forces acting on an object at the same time. What do we call the total of all these forces working on the same object?
Net Force
A box is lifted straight upward with 50 N of force. Gravity pulls downward with 35 N. What is the magnitude and direction of the net force?
15 N upward