MOTION DURING EQUILIBRIUM

Time is always on the side…

REVIEW

• We have seen so far 2 types of motion, both related to a type of equilibrium.

• In both motions, there is a kinematic variable that remains constant.

• For now, we will stick to translational motions.

TRANSLATIONS

EQUILIBRIUM• static

• dynamic

MOTION• @ rest

• uniform

TRANSLATIONS

EQUILIBRIUM• static

1. Constant kinematic variable

• Dynamic1. Constant kinematic variable

MOTION• @ rest

1. position

• Uniform1. velocity

Kinematic Variables

• From kines- – motion.• Used to describe the motion of the object

over time.• They are position, velocity and acceleration.• Acceleration is the rate of change in velocity.• Acceleration will only be present if impulse is

present.

MOTION GRAPHS

• Kinematic variables are used to graphically show motion and changes in motion over time.

• The 3 possible graphs are: position-time, velocity-time and acceleration-time graphs.

• In motion graphs, time is always in the x-axis.

OBJECT @ REST

• Position never changes. Position is constant.• Position is the location of the object relative to

a reference point.• Because the position never changes, the

velocity of an object at rest is also zero.

Object at rest

d v

? ?t t

Object at rest

d v

?t t

Object at rest

d v

0 t 0 t

Object in Uniform Motion

d v

? ?t t

Object in Uniform Motion

d v

?t t

Object in Uniform Motion

d v

0 t 0 t

Position-time Graphs

d v

slope?

0 t 0 t

Position-time Graphs

d v

slope = rise over run

0 t 0 t

Position-time Graphs

d slope = v

0 t 0 t

Position-time Graphs

d slopv = v

0 t 0 t

Position-time Graphs

To go from… to…

d v

find slope a

0 t 0 t

MOTION GRAPHSObject @ rest

d v a

?

0 t 0 t 0 t

Uniform Motion d v a

?

0 t 0 t 0 t

MOTION GRAPHSObject @ rest

d v a

?

0 t 0 t 0 t

Uniform Motion d v a

?

0 t 0 t 0 t

MOTION GRAPHSObject @ rest

d v a

slope slope

?

0 t 0 t 0 t

Uniform Motion d v a

slope slope ?

0 t 0 t 0 t

THAT’S ALL, FOLKS…

… FOR TODAY.