Force Fundamentals
A push or a pull exerted on an object by another object.
What is a Force?
This category of force requires objects to be physically touching to exist.
What is a contact force?
This force always acts in the direction opposite to an object's motion.
What is friction?
These images "free" an object from its surroundings to show all the forces acting upon it.
What are Free Body Diagrams (FBD)?
This mathematical formula relates net force, mass, and acceleration.
What is Fnet = ma?
The SI unit used to measure the magnitude of a force.
What is a Newton?
This field force attracts all mass to all other mass and always points toward the center of the Earth.
What is gravity?
This is the tendency of an object to resist any change in its motion.
What is inertia?
When all forces acting on an object are added together, the sum is called this.
What is the Net Force (Fnet)?
The net force acting on a 2 kg box accelerating at 200 m/s^2 left.
What is 400 N left?
Because forces include a number, a unit, and a direction, they are classified as this type of mathematical quantity.
What is a vector?
This specific contact force is transmitted through a string, rope, or cable.
What is tension?
If you are on the Moon, your weight changes significantly, but this property—which determines your resistance to acceleration—remains exactly the same as it is on Earth.
What is mass or inertia?
This support force acts perpendicular to a surface and prevents you from falling through your chair.
What is normal force?
A 2 kg toy car is pushed with a net force of 10 N. This is the resulting acceleration of the car.
What is 5 m/s2?
The "Interaction Rule" states that this is the minimum number of materials that must be interacting for a force to be present
What is two?
This upward contact force is exerted by a fluid (like water or air) on an object.
What is buoyancy?
In a vacuum (a space with no air), a feather and a hammer dropped at the same time will hit the ground simultaneously. This is because this specific force, which usually depends on surface area and speed, is absent
What is air resistance?
If a buoy has a weight of 490 N down and a buoyant force of 490 N up, its net force is this value.
What is 0 N? (Balanced)
An object accelerates at 2 m/s^2 when a 50 N net force is applied to it. This is the mass of the object?
What is 25 kg?
This is the specific amount of force required to accelerate a 1 kg mass at a rate of 1 m/s^2
What is 1 Newton?
While mass is the amount of matter in an object, this term refers specifically to the force of gravity acting on that mass.
What is weight?
According to Newton’s First Law, an object in motion stays in motion unless acted upon by an external force. In the real world, a rolling ball eventually stops; identify the specific force responsible for this and explain why it doesn't "violate" the law of inertia?
What is Friction? (It doesn't violate the law because friction is the "unbalanced external force" required to change the ball's state of motion)
A box is pushed 100 N to the right while friction pulls 40 N to the left. If the box is experiencing 200 N of gravity and 200 N of Normal force, this is the resulting net force.
A rocket in space (no friction) uses a 5,000 N thruster to accelerate at 5 m/s^2. This is the total mass of the rocket.
What is 1,000 kg?