Unit 8 forces and energy vocab

Force:

A push or pull exerted on an object

Friction:

force that opposes the sliding motion between two touching surfaces

Applied Force:

force causing a push or pull on an object not involving a string, rope or chain

Air Resistance:

the force exerted by air that opposes the motion of an object moving through it

Gravity:

attractive force between two objects that depends on the masses of the objects and the

distance between them.

Input Force:

the external force applied to a simple machine, such as a lever or pulley, to perform a

task

Output Force:

the force exerted by a machine to perform a task.

Output Force:

the force exerted by a machine to perform a task

Acceleration:

rate of change of velocity; can be calculated by dividing the change in velocity by the

time it takes the change to occur

Balanced Forces:

Forces are typically equal in strength and acting in opposite directions; object

remains at rest or in constant motion

Unbalanced Forces:

Forces may be unequal in strength or acting in directions NOT opposite each

other; Object accelerates in direction of net force

Inertia:

tendency of an object to resist any change in its motion

Momentum:

property of a moving object that equals its mass times its velocity.

Motion:

a change in an object’s position relative to a reference point.

Velocity:

the speed and direction of a moving object

Impulse:

force acting for a specific amount of time that results in a change in momentum; equal to

the change in momentum

Newton’s 1st Law of Motion:

states that an object moving at a constant velocity keeps moving at that

velocity unless an unbalanced force acts on it.

Newton’s 2nd Law of Motion:

states that the acceleration of an object is in the same direction as the

net force on the object, and that the acceleration equals the net force divided by its mass.

Newton’s 3rd Law of Motion:

states that when one object exerts a force on a second object, the

second object exerts a force on the first object that is equal in strength and in the opposite direction.

Law of Conservation of Momentum:

states that if no external forces act on a group of objects, their

total momentum does not change.

Law of Conservation of Momentum:

states that if no external forces act on a group of objects, their

total momentum does not change.

Gravitational Potential Energy:

energy that is due to the gravitational force between objects, often

dependent on the position of the object.

Elastic Potential Energy:

Energy that is stored by compressing or stretching an object

Potential Energy:

energy that is stored due to the interactions between objects

Kinetic Energy:

energy a moving object has because of its motion; determined by the mass and

speed of the object

Law of Conservation of Energy:

states that energy cannot be created or destroyed.

Weight:

gravitational force exerted on an object

Work:

transfer of energy when a force is applied over a distance; measured in joules.

Joule:

SI unit of work and energy.

Newton:

SI unit of force; the force required to accelerate a one-kilogram mass at a rate of one meter

per second squared.

Power:

rate at which energy is converted; measured in watts (W)