Motion and Forces

1
Motion and Forces
2
Objectives

• Relate speed to distance and time
• Recognize that moving objects have momentum
• Measure the effect of air resistance on sheets of
  paper with different shapes
• Design and create a shape from a piece of paper
  that maximizes air resistance
• Study the effect of mass and velocity of a moving
  object on its momentum
• Build and calibrate an instrument that measures
  force
• Measure how much force it takes to stretch a
  human hair until it breaks

3
Essential Questions

• What is the relationship between speed, distance,
  and time?
• What factors affect air resistance?
• Which object has more momentum?

4
Force

• The cause of acceleration, or change in an
  objects velocity.Force is measured in Newtons.
• 1 Newton 1 Kg x 1m/squared seconds

5

• Speed describes how fast an object moves
• Speed is the distance traveled divided by the
  time interval during which the motion occurred
• Sd/t

6
Velocity

• Velocity describes both speed and direction
• Vd/t with direction

7
Acceleration

• Acceleration is any change in velocity which is
  caused by a force
• a?v/t

8
Momentum

• A quantity defined as the product of an objects
  mass and its velocity.
• Pmv

9
Friction

• The force between two objects in contact that
  opposes the motion of either object.
• Frictional force varies depending on the surfaces
  in contact.
• Air resistance is a form of friction.

10
Gravity

• The attraction between two particles of matter
  due to their mass.
• Gravitational force depends on the mass of the
  two objects, and the distance between them.

11
Newtons First Law

• An object at rest remains at rest and an object
  in motion maintains its velocity unless it
  experiences an unbalanced force.

12
Newtons Second Law

• The unbalanced force acting on an object equals
  the objects mass times its acceleration.
• Fma

13
Newtons Third Law

• For every action force, there is an equal and
  opposite reaction force.

14
Experiment 1

• Testing the strength of human hair

15
Experiment 2

• Measuring the effects of air resistance

16
Experiment 3

• Measuring the speed and momentum of a toy car and
  observing acceleration