Force, energy and momentum Key Terms

Projectile motion assumptions

Assumptions made in projectile motion models include neglecting air resistance, considering the acceleration due to gravity as constant, and assuming the motion occurs in a uniform gravitational field.

Constant vertical acceleration

In projectile motion, the vertical acceleration is constant and equal to the acceleration due to gravity, typically denoted as g, which is approximately 9.81 m/s².

Newton's First Law of Motion

An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by a net external force.

Newton's Second Law of Motion

The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass, expressed as F = ma.

Newton's Second Law

The principle stating that the force acting on an object is equal to the mass of that object multiplied by its acceleration (F = ma).

Force

An interaction that causes an object to change its velocity, measured in newtons (N).

free-body diagram

A graphical representation used to visualize the forces acting on an object.

resultant force

The single force that represents the vector sum of all individual forces acting on an object.

resultant force

The single force that represents the vector sum of all individual forces acting on an object.

inertia

The property of an object to resist changes in its state of motion, directly related to its mass.

momentum

The product of an object's mass and its velocity, represented by the formula p = m x v, where p is momentum (kg m/s), m is mass (kg), and v is velocity (m/s).

impulse

The change in momentum of an object when a force is applied over a period of time, calculated using the formula impulse = F x t, where F is force (N) and t is time (s).

conservation of momentum

The principle stating that the total momentum of a closed system remains constant if no external forces act on it.

collision

An event where two or more bodies exert forces on each other for a relatively short time, resulting in a change of momentum.

Impulse

The change in momentum of an object when a force is applied over a period of time, calculated as the product of force and time.

Force-time graph

A graphical representation that shows the relationship between force applied to an object and the time duration over which the force is applied, used to determine impulse.

elastic collision

A collision in which kinetic energy is conserved, and the objects rebound without lasting deformation or generation of heat.

inelastic collision

A collision in which kinetic energy is not conserved, and the objects may stick together or deform, resulting in heat generation.

Work Done

The energy transferred when a force is applied to an object and it moves in the direction of the force.

Force

An interaction that causes an object to change its velocity, measured in newtons (N).

Kinetic Energy

The energy possessed by an object due to its motion, calculated using the formula Ek = 0.5 x m x v^2, where Ek is kinetic energy, m is mass, and v is velocity.

Gravitational Potential Energy

The energy stored in an object as it is raised above the ground, calculated using the formula Ep = m x g x h, where Ep is gravitational potential energy, m is mass, g is gravitational field strength, and h is height.

Power

The rate at which energy is transferred or converted, measured in watts (W).

Energy Transfer

The process of energy moving from one system or object to another, which can occur in various forms such as heat, work, or radiation.

efficiency

The ratio of useful output energy or power to total input energy or power, expressed as a percentage.

mechanical systems

Systems that use mechanical components to perform work or transfer energy, often analyzed for efficiency.

conservation of energy

The principle stating that energy cannot be created or destroyed, only transformed from one form to another.

energy transfer

The process of moving energy from one system or object to another, often involving conversion between different energy forms.

Energy Transfer

The process of moving energy from one store to another, such as from kinetic energy to potential energy.

Kinetic Energy

The energy possessed by an object due to its motion, calculated using the formula Ek = 0.5 x m x v^2.