Newton's 2nd Law
If the net force on a moving object is doubled while its mass stays constant, its acceleration will undergo this change.
Doubles
This specific type of friction prevents a stationary object from starting to move.
Static Friction
This fundamental property measures an object's quantity of matter and its resistance to acceleration (inertia).
Mass
As a falling skydiver picks up speed before opening their parachute, the air resistance acting on them undergoes this change. (Increases, Decreases, Remains the same)
Increases
When an elevator moves downward at a steady, constant speed of 8m/s, a scale inside reads (more than, less than, equal to) your actual weight.
Equal to
If you triple the mass of a wagon while keeping the net pulling force constant, its acceleration changes by this factor.
One-Third
You push a heavy desk with 45N of force and it remains completely at rest. This is the exact magnitude of the static friction force resisting your push.
45 N
The standard SI metric unit used to express weight.
Newton
When an object falling through air reaches terminal velocity, its acceleration equals this value.
Zero!
When an elevator accelerates upward from the ground floor, a bathroom scale inside reads (more than, less than, equal to) to your actual weight.
More than
The acceleration of a 12kg sled pushed across a frictionless surface by a net force of 60N
5 m/s^2
Flipping a long wooden board from its narrow edge to its wide face changes the sliding friction force by this amount when pushed at constant speed.
Zero!
A 40kg tool set is transported from Earth to a distant planet where gravity is 4m/s2. This is the mass of the tool set on that planet.
40 kg
At terminal velocity, the upward force of air resistance is equal in magnitude to this downward force.
Weight or Force of Gravity
If an elevator's support cable snaps and it enters free fall, a scale beneath a 70kg passenger will read this value.
0 N
When an object moves at a steady, unchanging velocity in a straight line, the net force acting on it must equal this value.
0 N
Stacking a second identical box on top of a sliding crate doubles the normal force, causing the sliding friction force to undergo this change.
Doubles
The weight on Earth (where g=10 m/s^2) of a person whose mass is 65kg.
650 N
Between a light basketball and a heavy bowling ball of identical physical mass and size dropped from a cliff, this ball will reach a higher terminal velocity.
Bowling Ball
A 60kg person (W=600N) stands on a scale in an elevator accelerating upward at 3 m/s^2. Assuming g=10 m/s^2, this is the reading on the scale.
780 N
A 10kg box is pushed to the right with an applied force of 80N while experiencing 20N of opposing friction. This is the resulting acceleration of the box.
6 m/s^2
On a microscopic level, friction between two solid surfaces sliding past each other is primarily caused by these two factors.
surface roughness/imperfections and intermolecular attraction
Heavy and light objects fall at the exact same rate in a vacuum because the heavier object's greater gravitational weight is balanced by this property.
Proportionally greater mass or inertia
Deploying a parachute lowers a skydiver's terminal velocity primarily by increasing this physical property.
Surface Area
An elevator moving upward toward the top floor slows down as it arrives. A scale beneath a passenger reads (more than, less than, equal to) their normal weight.
Less than