do now: roll the marble to your elbow buddy. what are 2 things you can change about the motion of a...
TRANSCRIPT
Do Now:
Roll the marble to your elbow buddy.
What are 2 things you can change about the motion of a rolling marble? Record your ideas in your new packet p 0.
Motion
SWBAT: explain when an object is in motion and how it is in motion relative to a reference point
• Vocabulary:• Motion: an object is in motion when its
distance from another object is changing •
Reference point
• Sometimes it is not so easy to tell if something is moving – we are always moving
Relative Motion
• Am I moving?
Compared to the tree?
Compared to the windshield?
Reference point
• reference point: a reference point is a place or object used for comparison to determine if something is moving
• Measuring motion always depends on a reference point
Do Now:
Make a ramp with the yellow bin and the piece of wood. Race two objects down the ramp.
Which object rolls faster? How can you tell?
Speed
• Speed = distance in one unit of time
• Speed = distance / time
Speed does not have to be FAST!
Do Now
1. How do you know an object is in motion?
2. Which is faster, a runner who moves 100 meters in 10 seconds, or a runner who moves 100 meters in 20 seconds? How do you know?
Speed
Category 1
0
1
2
3
4
5
6
Time in sec
Distance in m
Do NOW: Using what you learned yesterday write 2 sentences about this graph.
Velocity
• velocity = the speed and the direction of an object’s movement
Velocity
• We use meters per second (m/s) to measure distance
• mm: 1,000mm = 1 m _
• Cm: 100 cm = 1m ______
• Km: 1000 m = 1 km ___________________________________etc
DO NOW
• Use the words speed, distance, and time. Tell me about the relationship of speed to distance if the time stays the same.
• As distance traveled increases, speed ____________.
• As speed increases, distance traveled ____________.
Velocity
• velocity = the speed and the direction of an object’s movement
Acceleration
• SWBAT describe what happens to the motion of an object as it accelerates,
• SWBAT define and identify acceleration
Acceleration
• Acceleration: rate of velocity change in either speed or direction.
• Acceleration can be increasing speed, decreasing speed or change of direction.
• Acceleration= (final v – initial v) / time
Acceleration – change in speed or direction
Acceleration? Yes or NO?
Acceleration? Yes or NO?
Poem
• Use the words speed, velocity and acceleration in a poem. Make sure it shows you know the meaning of each term.
• Other words to use, motion, rate, change
Do Now:
• Look at an object on your desk that is not in motion.
• Can you change its motion? Record how you did it in your notebook.
• Once it is in motion, can you change its motion? How? Record your observations.
Forces
• Force: a push or a pull• Includes STRENGTH and DIRECTION
Net Forces
• Net force: overall force on an object after all forces are added together,
• If Net force is not zero it is unbalanced force
• An unbalanced force acting on an object will change an object’s motion
Balanced Forces
• BALANCED FORCES: equal forces acting in opposite directions
• A balanced force will not change an object’s direction
Tug-O-War
• Draw a diagram of what happened in our game. Be sure to label the forces for each team with arrows.
• Was the force balanced or unbalanced?• Was there a net force? Was there motion? Which
direction?• How could we make it a balanced force?• Thinking question 1: what other forces are acting on us
in this game?• Thinking question 2: what properties make force bigger?
SWBAT: State Newton’s first law of motion, and define inertia
• Inertia: the tendency of an object to resist change in motion• Newton’s first law of motion states
that an object in motion will remain in motion and an object at rest will remain at rest unless acted upon by an unbalanced force
http://teachertech.rice.edu/Participants/louviere/Newton/
Mrs. Levin video
FORCE
• Force depends on both mass and acceleration• Force is measured in Newtons• Force = Mass x Acceleration• F= M x A
Newton’s Second Law of Motion
• Force depends on mass and acceleration
Force = Mass x AccelerationF= M x AForce is measured in Newtons (N)
DO NOW
• When you go sledding, what force makes you slide down the hill? • What force stops you? • Would you go as far if there wasn’t
any snow on the hill? • Why?
Friction and Gravity
• Friction and gravity are two forces that affect nearly all motion
• What determines the strength of the force of friction?
Do Now:
• Place the wooden block on top of the board on one of the strips of material.
• While you gently hold the block in place, have a partner pull the board out from under the block so the block slides along the strip, not across – don’t rip the strips.
• Does the material make a difference in how hard your partner needs to pull?
• Switch jobs with your partners.
Friction Force in N (p. 27)Board Sandpaper Rubber Cork
Wooden block
Block with weight
1. Tilt board.2. Slide wooden block up board. Measure and record force in Newtons(N).3. Hook metal weight on top of block4. Slide both up board. Measure and record force in N.5. What 2 factors affect friction?
What determines the strength of the force of friction?
• The type of the two surfaces • The force which they are pressed together
(how hard they rub)• Wheels, wax and oil reduce friction
• Heat is produced as a result of friction – some mechanical energy turns into thermal energyhttp://videos.howstuffworks.com/discovery/28985-coming-home-from-space-space-shuttle-reentry-video.htm
Gravity
Line up a penny and quarter on top of a ruler at the side of your desk. Have one observer watch the floor. Another observer watches the ruler. Tip the ruler so that both the penny and quarter fall at the same time.
Which hits first? (You may have to try it several times.)
Gravity
• All objects put a gravitational force on other objects.
• The more mass the object has the more gravitational force. (That’s why we feel the earth’s and moon gravity but you can’t feel the gravity of your pencil)
• Mass does not affect the acceleration of gravity.
• Air resistance does affect rate of acceleration.
Exit
http://videos.howstuffworks.com/discovery/28985-coming-home-from-space-space-shuttle-reentry-video.htm
Do now:
• Line up 5 marbles in the pencil groove on top of your desk. Roll another marble along the groove, hitting the 5 marbles on end. Observe.
• Do it again but now roll 2 marbles together into the 5. Observe what happens.
• How can you use Newton’s laws to explain your observation?
Newton’s 3rd law• For every action, there is an equal and opposite reaction
• If an object exerts a force on a 2nd object the 2nd object exerts and equal and opposite force on the first object
Do Now: Explain the Cartoon
Newton’s 3rd Law of Motion
• For every action there is an EQUAL and OPPOSITE reaction
Hammer
The 2 persons are pushing each other on ice.(so no outside force). The grandma has twice the mass (inertia) as thelittle girl. Are they going to feel the same force ? according to what law ?Are they going to move as fast ? Which one is going to move faster ?
Use Newton’s 3rd law to describe why the girl ended up in the water
How does this show Newton’s 3rd law