Test 2- Motion

Motion

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

motion is ________

relative

Displacement

how far from the “starting point”

displacement calculation

• add displacement in the same direction

• subtract displacements in opposite direction

• displacements that are not in the same or opposite direction cannot be added directly

  • use pythagorean theorem: a2+b2=c²

Distance

how far (which is length) an object travels

• total motion

speed

change in distance over an amount of time (how fast something is going)

constant speed

the object travels at the same speed

average speed

total distance divided by total time

insantaneous speed

speed at that instant

• example: the reading on a car speedometer

speed formula

distance/time

• unit is meter/second (m/s)

distance, speed, time

D= S x T

S= D/T

T= D/S

velocity

the speed and direction

velocity calculation

d/t

acceleration

change in an object’s velocity over time

• unit is m/s²

• change in speed, direction, or both causes acceleration

Freefall

acceleration of a falling object due to gravity

• 9.8 m/s²

projectile motion

anything shot or thrown

• motion follows a curved path

momentum

product of mass and velocity

• p=mv

• unit is kg-m/s