Pushes and Pulls Affect Motion Kindergarten Open Source Image

Content Topics Connection of motion to pushes and pulls Inertia versus force Force, mass, and motion

Pushes & Pulls We call a push or pull a force. Forces can cause a change in motion.

http://www.grc.nasa.gov/WWW/k-12/airplane/socforce.html

Motion A push will cause motion. A pull will cause motion. Open Source Image

Changes in Motion Changes in motion may be any of the following. Slowing down Speeding up Stopping Going Changing direction Jumping Falling

Practice What can cause the change motion? What is an example of this happening? Slowing down Using your muscles or a brake, to move slower Speeding up Running faster, peddling faster Stopping Using your muscles or a brake to stop Going Walking, running, riding Changing direction Turning, going in a circle, jumping up and falling down Jumping Moving up away from the ground Falling Moving down toward the ground

Corners There is a change in direction, a change in motion, when a car goes through a corner. How does the change in motion happen? Turning the wheel, the road pushing

Inertia Objects will keep their motion unless they are forced to change. If a ball is at rest, it will not move on its own. If a ball is in motion, it will not stop on its own. http://www.physicsclassroom.com/mmedia/newtlaws/il.cfm

Inertia and Mass Inertia depends on mass. More mass  More inertia  Harder to change motion

Practice Will the toy cars move by themselves? No, the cars need a push or a pull to move

Forces Forces make an object move differently. Stronger forces cause bigger changes in motion. F = ma F = force (push or pull) m = mass (the amount of material contained in the object) a = acceleration (change in speed or direction, change in motion)

More Force  More Change The harder you push on the peddles, the faster your bike goes. Open Source Image

More Force  More Change The harder you kick the soccer ball, the farther it goes. Open Source Image

More Force  More Change The stronger your pull is on the wagon, the faster it will go. Open Source Image

A strong push will move the ice block more. Practice Will a gentle push or a strong push move the ice block more? A strong push will move the ice block more. Open Source Image

Newton’s 3rd Law of Motion When two objects interact, they create equal and opposite forces on each other. Same Pull Opposite Directions F1 = −F2 Open Source Image

Same Force If the pushes are the same, the motion will not change. Person at rest stays at rest. If the pulls are the same, the motion will not change. The pull of the wagon is the same as the pull of the person. Open Source Images

Practice Two people give the same amount of push to toy cars. One toy car is heavier than the other. Which toy car travels farther? The lighter toy car will travel farther if the push on each is the same. You and your friend each kick a soccer ball. Your ball travels farther. Which ball had the stronger push? Your ball had the stronger push because it went farther.

More Practice One person sits in a wagon that is stopped. What needs to happen to change the motion of the wagon? Someone needs to pull or push the wagon for it to start moving. Your marble is about to roll off the table, how can you change the direction of the marble without stopping it? Use something to make the marble turn a corner, or bounce off a barrier and change direction.

Gaming Practice You want to make your person in the video move to the right. What do you need to do to the game controller? You need to push the control knob the direction you want to make something in the game move.