Forces and Motion DCA Review

Vocabulary flashcards covering key definitions, principles of Newton's laws of motion, force calculations, and collision concepts from the Forces and Motion DCA Review.

Newton's 1st Law

The law stating that an object at rest stays at rest and an object in motion stays in motion unless acted upon by an outside force (e.g., a box on the ground will not move unless something pushes it).

Newton's 2nd Law

The physical law represented by the formula $F = m \times a$, meaning the force required to move or accelerate an object depends on its mass and acceleration (e.g., a heavier object takes more force to move).

Newton's 3rd Law

The law stating that for every action force, there is an equal and opposite reaction force (e.g., the forces exerted when a person is walking, or collisions exerting equal strength forces in opposite directions).

Friction

The force interaction between an object and a surface that acts in opposition to motion and causes an object to slow down.

Low-Friction Surface

A surface type, such as ice, that provides minimal resistance to the motion of an object.

Balanced Forces

Forces that are equal in size and opposite in direction, resulting in a net force of zero and no acceleration (e.g., a soccer ball at rest or moving at a constant velocity).

Unbalanced Forces

Forces that do not cancel out, resulting in a non-zero net force that causes an object to accelerate (e.g., a soccer ball kicked hard toward the goal).

Collision Force Rule

The principle based on Newton's 3rd Law that in any collision, the forces exerted on each object are equal in magnitude/size and opposite in direction.

Mass and Acceleration Relationship (Collision)

Because collisions produce equal strength forces on both objects, the object with greater mass experiences less acceleration, while the object with less mass experiences greater acceleration.

Inertia (Skateboarder Scenario)

The continuation of a rider's forward motion onto the sidewalk when their skateboard abruptly stops at a curb, governed by Newton's 1st Law because their body was in motion and wants to stay in motion.

Balanced Applied and Frictional Forces

A state in which an applied push of $50\,N$ to the right is canceled out by a friction force of $50\,N$ to the left, resulting in a net force of $50\,N - 50\,N = 0\,N$ and preventing movement.

Frictionless Motion

The perpetual motion of an object sliding on a frictionless surface, which will never stop unless an opposing outside force is applied.

Hammer Impact Force Calculation

The calculated force exerted by a $1.2\,kg$ hammer accelerating at $9.5\,m/s^2$, determined by $F = m \times a$ to be $1.2\,kg \times 9.5\,m/s^2 = 11.4\,N$.

Horizontal Net Force Calculation ($60\,N$ and $30\,N$)

The net horizontal force resulting from opposing forces of $60\,N$ to the right and $30\,N$ to the left, calculated as $+60\,N - 30\,N = 30\,N$.

Vertical Net Force Calculation ($30\,N$ and $10\,N$)

The net vertical force resulting from opposing upward and downward forces of $30\,N$ and $10\,N$, calculated as $+30\,N - 10\,N = 20\,N$.

Least Force Requirement (Chairs Comparison)

The concept that when objects undergo the same change in speed ($3\,m/s$), the object with less mass (the yellow chair at $10\,kg$) requires the least force to accelerate compared to heavier objects ($12\,kg$ chairs).