Physics Mechanics & Momentum Practice

Vocabulary flashcards covering the core concepts of mechanics, including momentum, gravity, springs, work, and energy based on the lecture material.

Momentum

A quantity calculated as the product of mass and velocity. A heavy truck has more than a passenger car at the same speed due to its greater mass.

Conservation of Momentum

The principle stating that the net change in total momentum of a system (such as two cars crashing or two carts pushing off) stays at $0 kg\,m/s$ if no external forces act.

Recoil

The backward movement of an object (like a girl on ice or an astronaut) resulting from throwing another mass forward in order to conserve momentum.

Impulse (\Delta p)

The change in momentum of an object, which can be found by calculating the area under a Force vs. Time graph.

Impact Time

The duration of contact during a collision. Increasing this (via mats or crumpling guardrails) reduces the average force for a given impulse.

Uniform Circular Motion

Movement at a constant speed in a circular path where velocity magnitude is constant but direction is always changing, and the net force is applied towards the center.

Centripetal Acceleration

The acceleration in circular motion directed inward. If velocity is tripled ($3v$) while the radius stays the same, the acceleration increases to $9a$.

Newton's Law of Universal Gravitation

The law stating that the gravitational force ($F_g$) is proportional to the masses and inversely proportional to the square of the distance between them. Earth and the Moon pull each other equally.

Acceleration due to Gravity ($g$)

The rate at which objects accelerate toward a planet's center. For a person on Mars, this value is approximately $3.71\,m/s^2$.

Spring Constant ($k$)

Represented by the slope of a Force vs. Displacement ($x$) graph, it measures the stiffness of a spring. Flexible springs have a lower value than stiff springs.

Elastic Potential Energy ($EPE$)

The energy stored in a spring, calculated as $\frac{1}{2}kx^2$. Tripling the stretch distance ($3x$) results in nine times ($9x$) the energy.

Work

Mechanical energy transfer defined by a force acting over a parallel movement. No work is done if the force is perpendicular ($90^{\circ}$) to the motion.

Negative Work

Work done by a force that acts in the opposite direction of the displacement, such as friction force on a sliding box.

Kinetic Energy ($KE$)

The energy of motion, calculated as $\frac{1}{2}mv^2$. If an object's linear velocity is tripled, this value scales to $9$ times the original.

Gravitational Potential Energy ($GPE$)

Stored spatial energy related to height. It remains at a constant zero if an object moves only on a flat, level ground.

Total Mechanical Energy

The sum of the kinetic and potential energies in a system ($KE + GPE + EPE$).

Power

The rate at which work is delivered or energy is spent. If two people do the same work but one finishes in half the time, that person has delivered twice the power.

Thermal Energy

The form of energy to which mechanical energy is often lost (via friction), causing a roller coaster car to fail to reach its starting height on a far loop.