10-3: Newton’s 1st and 2nd Laws

10-3: Newton’s 1st and 2nd Laws

8th Grade Physical Sciences


Purpose

Students will be able to:

1. State Newton’s first law of motion.

2. State Newton’s second law of motion.

Newton’s 1st Law of Motion

• An object will remain at rest or will move at a constant velocity unless it is acted upon by an unbalanced force.


http://www.google.com/url?sa=i&rct=j&q=newton's+first+law&source=images&cd=&cad=rja&docid=UPUvC1S6_7HV9M&tbnid=mjRNojXmMc3SvM:&ved=0CAUQjRw&url=http://www.glogster.com/abbeytabby21/newton-s-first-law-of-motion/g-6na7u7q33dkls7919iu3aa0&ei=hO1HUfO2HYnXiALrhYGwBg&bvm=bv.44011176,d.cGE&psig=AFQjCNF93tMAU_LaJiYwRy4jttmgeYhTnQ&ust=1363754736008039


• An unbalanced force will cause an object to speed up, slow down, or change direction.


http://www.google.com/url?sa=i&rct=j&q=newton's+first+law&source=images&cd=&cad=rja&docid=UPUvC1S6_7HV9M&tbnid=mjRNojXmMc3SvM:&ved=0CAUQjRw&url=http://www.glogster.com/abbeytabby21/newton-s-first-law-of-motion/g-6na7u7q33dkls7919iu3aa0&ei=hO1HUfO2HYnXiALrhYGwBg&bvm=bv.44011176,d.cGE&psig=AFQjCNF93tMAU_LaJiYwRy4jttmgeYhTnQ&ust=1363754736008039


• On Earth an object, like a baseball, will not go forever after being hit.

• Gravity and air resistance act on it to bring it to a stop.


http://www.google.com/url?sa=i&rct=j&q=baseball&source=images&cd=&cad=rja&docid=EeP9-gV6phlOeM&tbnid=1ySLpvdzYwbJ9M:&ved=0CAUQjRw&url=http://en.wikipedia.org/wiki/Batting_(baseball)&ei=_EhJUYPiBYK4iwL0lIG4Bw&bvm=bv.44011176,d.cGE&psig=AFQjCNE662suYu4-YidEej19Cuh9LIYnjg&ust=1363843686898553


• However, in space it WOULD go forever – or until it hit something.



• Objects have inertia.

• Inertia is the tendency of an object to resist a change in motion.


http://www.google.com/url?sa=i&rct=j&q=inertia&source=images&cd=&cad=rja&docid=W0VM2i85MUMI5M&tbnid=LXb95XBLPvyfJM:&ved=0CAUQjRw&url=http://systematicrelativestrength.com/2011/07/08/never-underestimate-inertia/&ei=BktJUZGeDuS9igKA94GoAw&bvm=bv.44011176,d.cGE&psig=AFQjCNGR4uwMGFcigmfb1gsCIVby3WihrA&ust=1363844213976063



http://www.google.com/url?sa=i&rct=j&q=inertia+table+cloth&source=images&cd=&cad=rja&docid=Y6JcfoV02U1i5M&tbnid=MOpTpjo7zAGUdM:&ved=0CAUQjRw&url=http://www.watchmojo.com/tv/Grab/Howcast/4012967/&ei=-0tJUYW4L6qYiAL3woHwBw&bvm=bv.44011176,d.cGE&psig=AFQjCNEp9Z3Jypl5Tpr-R4id7cRS-dzAUQ&ust=1363844373816830


• Newton’s 1st Law is also called the Law of Inertia.

• Objects with a large mass have greater inertia than with a small mass.


http://www.google.com/url?sa=i&rct=j&q=locomotive+train&source=images&cd=&cad=rja&docid=flF3X70jcGTFSM&tbnid=bSQtH4EKwOwA3M:&ved=0CAUQjRw&url=http://www.listofimages.com/steam-locomotive-railway-train-steam-train-rail-locomotive-steam-other.html&ei=Jk1JUZ2zHMmtiQL0_oCwCA&bvm=bv.44011176,d.cGE&psig=AFQjCNH51qe8zoTWyzLVm6PhR6YD5bPVpA&ust=1363844757032217

http://www.google.com/url?sa=i&rct=j&q=locomotive+train+toy&source=images&cd=&cad=rja&docid=ZsYxtjUzNm9VLM&tbnid=Qu4WSr66xgctGM:&ved=0CAUQjRw&url=http://www.talismancoins.com/servlet/Detail?no=986&ei=gk1JUdb2FoqtigL4-oCABA&bvm=bv.44011176,d.cGE&psig=AFQjCNHPZUJe9sY5L0BysXupgHHKiZfzqQ&ust=1363844804294034

Newton’s 2nd Law of Motion

• Acceleration depends on the net force acting on an object and the object’s mass.


Newton’s 2nd Law of Motion

• The formula for this relationship is acceleration equals the net force divided by the mass. Net force Accel = -------------- Mass


How to increase acceleration


Remove Mass

Remove Mass

Increase Force

Net force Accel = -------------- Mass

http://www.google.com/url?sa=i&rct=j&q=lightweight+race+car&source=images&cd=&cad=rja&docid=fRk3APRlIOGfnM&tbnid=_m5cxJmlPOIG7M:&ved=0CAUQjRw&url=http%3A%2F%2Fsportcar5.blogspot.com.es%2F2010%2F11%2Fmob-toyota-sports-cars-concept.html&ei=GpRKUfmbEamciQKF7YDQDg&psig=AFQjCNGjgsRX1uasKcVKDj-WKS2tIXsiuw&ust=1363928447444624

http://www.google.com/url?sa=i&rct=j&q=pulling+wagon&source=images&cd=&cad=rja&docid=pMHcO6AbwikbyM&tbnid=yg_wjmjTZfE2oM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.flickr.com%2Fphotos%2Ftselliottpics%2F4005744940%2F&ei=cpRKUaZiofuKApexgQg&psig=AFQjCNGE8skkBJrB1WhocFL1u0kxfKiwJQ&ust=1363928537230114

http://www.google.com/url?sa=i&rct=j&q=pulling+wagon&source=images&cd=&cad=rja&docid=1Ekgd4fgVvYkKM&tbnid=_zzkBT6rT0Nr0M:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.waynedavisphotography.com%2Fportfolio-people.html&ei=kpRKUb3PKurJiwLEkIBo&psig=AFQjCNGE8skkBJrB1WhocFL1u0kxfKiwJQ&ust=1363928537230114

http://www.google.com/url?sa=i&rct=j&q=dad+pulling+wagon+of+pumpkins&source=images&cd=&cad=rja&docid=tTW95HVXPMVAQM&tbnid=tUIFWphkoNGJrM:&ved=0CAUQjRw&url=http%3A%2F%2Fblessedspears.blogspot.com%2F2008%2F11%2Fpumpkin-patch-08.html&ei=XJZKUfeQAbL9iQLUqIDwBg&psig=AFQjCNG2outjKWzm3ErFWYroT85Gf3giZQ&ust=1363928953224608


Calculating Force A speedboat pulls a 55-kg water-skier. The skier accelerates at 2.0 m/s2. Calculate the net force that causes this acceleration.

10-3: Newton’s 1st and 2nd Laws Summary

• Newton’s 1st law says an object at rest or in motion will remain so until unbalanced forces act on it.

• This laws is also referred to as the law of inertia.

• His 2nd law says acceleration depends on the force acting on the object and the objects mass (a = F/m).

10-3: Newton’s 1st and 2nd Laws

Documents

Transcript of 10-3: Newton’s 1st and 2nd Laws