Motion and Forces - PowerPoint PPT Presentation

Loading...

PPT – Motion and Forces PowerPoint presentation | free to download - id: 5a39e7-YmMwM



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Motion and Forces

Description:

Motion and Forces LETS START WITH MOTION How can you prove that an object is moving? MOTION Motion- An object is in motion when the distance from another object is ... – PowerPoint PPT presentation

Number of Views:97
Avg rating:3.0/5.0
Slides: 32
Provided by: SedwayMid
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Motion and Forces


1
Motion and Forces
2
LETS START WITH MOTION
  • How can you prove that an object is moving?

3
MOTION
  • Motion- An object is in motion when the distance
    from another object is changing.
  • Reference Point- A place or object used for
    comparison to determine if something is in
    motion.
  • An object is in motion if it changes position
    relative to a reference point.

4
CALCULATING SPEED
  • Speed Distance / Time
  • If you measure distance in meters and time in
    seconds you express speed in m/s
  • Give an example of the speed a snail could
    travel.
  • Constant speed-When the speed of an object does
    not change
  • Average speed- Total distance / total time

5
MOTION
  • Velocity- Speed and direction
  • Acceleration- Rate at which velocity changes
    (increasing speed, decreasing speed, changing
    direction) m/s/s
  • EXAMPLES OF ACCELERATION???
  • Accelerationfinal velocity- initial velocity /
    time

6
Acceleration problems
  • Suppose a car moving in a straight line steadily
    increases its speed each second, first from 35 to
    40 km/hr, then from 40 to 45 km/hr, then from 45
    to 50 km/hr. What is its acceleration?

7
Acceleration problems continued
  • In 5 seconds a car moving in a straight line
    increases its speed from 50 km/hr to 65 km/hr
    while a truck goes from rest to 15 km/hr in one
    second. Which undergoes the greatest
    acceleration? What is the acceleration of each
    vehicle?

8
Think about this
  • The Cat bus is approaching Lone Mountain at 144
    cm/s. A person on the bus is facing forward and
    walking 36 cm/s relative to everything in the
    bus. The person is eating a hotdog which is
    entering his mouth at 2 cm/s. An ant on the
    hotdog is running away from the persons mouth at
    1cm/s. How fast is the ant approaching Lone
    Mountain?

9
NEWTONS FIRST LAW OF MOTION
  • Law of Inertia
  • An object at rest will remain at rest and an
    object that is moving will continue moving unless
    acted upon by an unbalanced force.
  • What do you think an unbalanced force is?

10
(No Transcript)
11
Unbalanced Force
12
UNBALANCED FORCE
  • Unbalanced forces cause an object to start
    moving, stop moving, or change direction. (an
    unbalanced force will cause an object to
    accelerate)
  • Net force- The overall force on an object after
    all the forces are added together

13
(No Transcript)
14
BALANCED FORCES
  • Balanced forces are equal forces acting in an
    opposite direction.
  • Balanced forces do not cause acceleration.

15
A force is just a push or a pull
16
MOMENTUM!!!
  • Mass x Velocity Momentum (P)
  • Increase the mass or the velocity to get more
    momentum.

17
Conservation of Momentum
  • Newtons Balls (Newtonian Demonstration)
  • Pool Table

18
NEWTONS SECOND LAW OF MOTION
  • Force, Mass, and Acceleration

19
(No Transcript)
20
UNITS
  • Mass- kg which equals 1000 grams (g)
  • Acceleration- m/s/s
  • Force- kg x m/s/s or Newton (N)
  • SAMPLE PROBLEM
  • A 52 kg water-skier is being pulled by a
    speedboat. The force causes her to accelerate at
    2m/s/s. Calculate the net force that causes this
    acceleration.

21
FRICTION
  • Friction- The force that one surface exerts on
    another when the two rub against each other.
  • Two factors- Type of surface and how hard they
    rub together.
  • Sliding friction- dry solid surfaces
  • Rolling friction- rolling over a surface
  • Fluid friction- object moves through a liquid or
    gas.

22
LAW OF UNIVERSAL GRAVITATION
  • Law of universal gravitation states that the
    force of gravity acts between all objects in the
    universe.
  • The strength of the force depends on the masses
    of the objects and the distance from them

23
GRAVITY
  • Free fall- when the only force acting on a
    falling object is gravity. (9.8m/s/s)
  • Do all objects regardless of mass fall at this
    rate? (water cup demo)
  • What about projectiles?

24
(No Transcript)
25
GRAVITY
  • Air resistance- a type of fluid friction that
    objects falling through air experience.
  • Paper vs.. Book
  • Weight- The measure of the force of gravity on an
    object (scale)
  • Mass- is a measure of the amount of matter in
    that object.

26
WEIGHT DUE TO GRAVITY
  • Remember Fma???
  • Weight mass x acceleration due to gravity
  • Weight mass(kg) x 9.8 m/s/s
  • The amount of force you apply to the ground in
    Newtons

27
NEWTONS THIRD LAW OF MOTION
  • ACTION AND REACTION

28
EVERY ACTION HAS AN EQUAL AND OPPOSITE REACTION!!!
29
3rd law only refers to forces on 2 different
objects
30
What about circular motion???
  • Bucket Demonstration
  • What is the centripetal force for a satellite?
  • Centripetal- center seeking
  • Centripetal force- any force that causes an
    object to move in a circle.

31
(No Transcript)
About PowerShow.com