Physics: Forces, Newton's Laws, and Incline Mechanics

Vocabulary practice flashcards covering Newton's laws of motion, friction, concurrent vectors, equilibrants, inclined planes, and related kinematic concepts.

Inertia (in Relation to Mass)

The tendency of an object to resist changes in its state of motion, which is determined strictly by its mass regardless of speed (for example, among objects ranging from $4.0\,\text{kg}$ to $16.0\,\text{kg}$, the $16.0\,\text{kg}$ object possesses the greatest inertia).

Newton ($\text{N}$)

The SI derived unit of force, equivalent to $1\,\text{kg}\cdot\text{m/s}^2$.

Acceleration under a Constant Unbalanced Force

A state in which an object experiences steady acceleration across elapsed time, represented graphically by a horizontal line of constant value on an acceleration versus time graph.

Acceleration of Connected Blocks on a Frictionless Surface

The shared acceleration of blocks pushed together across a frictionless plane, equal to the applied net force divided by the total mass (for example, a $12\,\text{N}$ force applied to a $1.0\,\text{kg}$ and a $2.0\,\text{kg}$ block produces an acceleration of $4.0\,\text{m/s}^2$).

Equilibrant Force Vector

A vector that acts concurrently with existing forces to establish equilibrium, resulting in a net force of $0\,\text{N}$.

Resultant of Concurrent Forces at $120^\circ$

The geometric condition where two equal forces of magnitude $30\,\text{N}$ acting concurrently at an angle of $120^\circ$ combine to produce a resultant force whose magnitude is also exactly $30\,\text{N}$.

Equilibrium Range of Concurrent Forces

The geometric rule that two concurrent forces (such as $3\,\text{N}$ and $4\,\text{N}$) can only be balanced by a third force whose magnitude lies within the possible range of their resultant ($1\,\text{N}$ to $7\,\text{N}$); thus, a $9\,\text{N}$ force cannot produce equilibrium.

Blukio vilkimas

A Lithuanian Christmas Eve tradition of dragging a log from house to house using ropes; when dragged at a constant velocity, the force of kinetic friction acting on the log is equal to the force exerted by the pullers.

Static Friction on an Incline

The frictional force acting on a stationary block on an inclined ramp, which equals the parallel component of the block's weight: the weight multiplied by $\sin(\theta)$.

Pulling Force at Constant Velocity (Wood on Wood)

The force parallel to the surface required to move a $1000\,\text{kg}$ wood block at a constant velocity of $10\,\text{m/s}$, which balances the kinetic friction force with a magnitude of $2,943\,\text{N}$.

Normal Force ($F_N$)

The contact force exerted by a surface perpendicular to the plane of contact on an object resting or sliding on it (such as a sled sliding down a $30^\circ$ hill).

Net Force on an Incline at Rest

The vector sum of all forces on an object that remains completely at rest on a surface (such as a $100\,\text{kg}$ person at rest on a drawbridge inclined up to $70^\circ$), which is always equal to $0\,\text{N}$.

Newton's Third Law Force Interaction

The principle stating that forces always occur in matched pairs equal in magnitude and opposite in direction, meaning that when a $120\,\text{kg}$ boy and a $60\,\text{kg}$ girl pull against each other with spring scales, the magnitude of the force recorded on the girl's scale is identical to that on the boy's scale over time.

Frictionless Incline Acceleration ($g \sin(\theta)$)

The acceleration of an object sliding freely down a frictionless ramp, calculated as $a = g \sin(\theta)$ ($.17\,\text{m/s}^2$ for a $100\,\text{kg}$ mass on a $1^\circ$ incline); because it is independent of mass, doubling the mass on a $45^\circ$ incline leaves the acceleration equal to the initial acceleration.

Constant Velocity Drag Force (Ant and Crumb)

The scenario where an ant dragging a crumb at a constant velocity exerts a force equal to the opposing friction force; if the crumb breaks in half while pulled with the same $.005\,\text{N}$ force, its acceleration doubles according to $a = \frac{F}{m}$.

Curved Incline Vertical Acceleration

The acceleration of a $50\,\text{kg}$ block at the top of a frictionless curved incline where the slope is vertical ($90^\circ$ with the ground), equal to the acceleration due to gravity ($9.81\,\text{m/s}^2$).

Normal Force on a Curved Surface at $30^\circ$

The perpendicular force exerted by a curved ramp's surface on a $50\,\text{kg}$ block when the incline forms a $30^\circ$ angle with the ground, given by $mg \cos(30^\circ)$.

Coefficient of Kinetic Friction ($\mu_k$)

The ratio of kinetic friction to the normal force ($\mu_k = \frac{a}{g}$ on level ground), yielding approximately $0.41$ when a block decelerates at $4\,\text{m/s}^2$, or approximately $0.15$ when a block traveling at $15\,\text{m/s}$ comes to a stop over $10\,\text{s}$.