motion

The state in which one's object 's distance from another is changing.

How do you determine if object is moving?

An object is in motion if it changes position relative to a reference point.

distance

The total length of the actual path between two points

Displacement

The length and direction of a straight line between starting and ending points

How do you calculate speed of a moving object?

Speed= distance/time

How do you calculate the average speed of an object?

average speed(v) = d/t

velocity

speed in a given direction

acceleration

the rate at which velocity changes with time

What three things does acceleration refer to?

1.  increasing speed

2.  decreasing speed

3.  changing direction

How do you calculate acceleration?

Acceleration = final velocity - initial velocity/time

energy

the ability to do work or cause change.

kinetic energy

an object has due to it motion

potential  energy

stored energy that results from the position or shape of an object.

Law of conservation of energy

The rule that energy cannot be created or destroyed.

force

a push or pull exerted on an object

Newton(N)

What is the SI unit for force?

Balanced forces

What force acts on an object do not change the object's velocity.

unbalanced forces

What force acts on an object result in a net force and cause a change in the object's velocity.

friction

The force that one surface exerts on another when the two surfaces rub against each other.

Static friction

acts on objects that are not moving

(pushing a heavy desk across the floor)

Sliding friction

when two solid surfaces slide over each other

rolling friction

when an object rolls across a surface

fluid friction

when a solid object moves  through a fluid

gravity

force that pulls objects toward each other

How do mass and distance affect the force of gravity between objects?

The force of gravity between objects increases with greater mass and decreases with greater distance.

weight

gravitational force exerted on a perosn or object at the surface of planet

gravitational force calculation

weight = mass  X acceleration due to gravity

free fall

the only force acting on an object is gravity, the object is said to be in free fall.  Its accelerating.  The force of gravity alone causes an object to acceleration in the downward direction.

air resistance

a type of fluid friction that acts on objects falling thrugh air.

object is elastic

its orignal shape after it is squeezed or stretched.

compression

Is an elastic force that squeezes or pushes matter together

tension

elastic force that stretches or pulls matter.

inertia

the tendency of an object to resist a change in motion

Newton's first law of motion is called the law of ______.

newton's first law of motion

States that an object will remain at rest or moving at a constant velocity unless it is acted upon by an unbalanced force.  An unbalanced force will cause an object to speed up, slow down, or change direction.

Newton's second law of motion

States that acceleration depends on the net force acting on the object and on the object's mass.

Newton's third law of motion

States that if one object exerts a force on another object, then the second object exerts force of equal strength in the opposite direciton on the first object.

also states every action there is an equal but opposite reaction.

centripetal force

a force that causes an object to move in a circle

density

the ratio of the mass of a substance to it volume

buoyant force

the upward force exerted by a fluid on submerged object.

acts in the direction opposite to the force of gravity, so it makes an object feel lighter.

Achimedes' principle

states that the buoyant force acting on a submerged object is equal to the weight of the volume of fluid displaced by the object.

speed

the line on a distance vs. time graph represents

time

on a distance vs. time graph, the x-axis represents

horizontal line

on a distance vs. time graph, how do you know if a runner's distance did not change.