FORCES & MOTION: Support Videos

(17)  Free Body Diagrams (1 of 2)

(October 17) These diagrams are also called force diagrams and help reinforce your understanding of balanced and unbalanced forces.  Remember that objects that are accelerating (speeding up, slowing down or changing direction) have an unbalanced force acting on them.

(18)   Free Body Diagrams (2 of 2)

(October 17) These diagrams are also called force diagrams and help reinforce your understanding of balanced and unbalanced forces.  Remember that objects that are accelerating (speeding up, slowing down or changing direction) have an unbalanced force acting on them.

(15)  Inverse Square Law

(October 15) Mr. Wright said this was cool, because it is. 

What two things determine an object's gravitational pull?  Mass and distance.  It makes sense that more massive objects (Sun) have greater gravitational force (pull) than less massive objects (Earth).  But how does distance affect an object's gravity?  

(16) Inverse Square Law (Part 2)

(October 14 ) -  Does Gravity Have a Value?

Watch from 31:28 - 36:30.

Physics professor Jim Al-Khalili investigates the amazing science of gravity and one of the most intriquing of scientists that figured out the mass of our planet.  A fundamental force of nature, gravity shapes our entire universe, sculpting galaxies and warping space and time. But gravity's strange powers, discovered by Albert Einstein, also affect our daily lives in the most unexpected ways. As Jim tells the story of gravity, it challenges his own understanding of the nature of reality.

(14) Gravity PowerPoint Slides

(October 15) - This is the recorded PowerPoint presentation shown in class.  Handout #15 was a copy of the slides.

(12)  Lacrosse Ball & Ping Pong Ball

(October 16) -  Why did we do this in class?  Conservation of momentum, that's why.  Watch it.  Can you explain why the ping pong ball rocketed into our classroom ceiling tiles?  The answer lies in what happened to the momentum of the lacrosse ball.

(13)  Lacrosse, Ping Pong & Golf Balls

(October 16) - It should make sense that the Ping Pong rocketed into our ceiling tiles because it took momentum from the more massive lacrosse ball.  It bounced higher because the lacrosse ball bounced less.  What would happen if we added more momentum to the system?  If we add two golf balls to the system, will more momentum be transferred into the Ping Pong ball?  Let's find out.  

(10) Momentum (4) - Inelastic Collisions

(October 11-12)  - Say hello to Timmy from South Park. Timmy agreed to join us in explaining momentum during an inelastic collision.  His friend, Eddie, also took part in the demonstration.  

(11) Momentum (5) - Timmy Figures Things Out

(October 11-12)  -  What if the Timmy/Eddie collision resulted in zero momentum?  That would mean that the collision resulted in a tangled mess of bumper cars with zero velocity.  Hmmm.  

What knowledge did such a collision give Timmy?  At wht velocity can HE do the pushing?  Let's just say that Timmy will will no longer get pushed around.  Hooray for nerds .  .  . or those that pay attention during physics instruction.

(8) MOMENTUM (2): Collisions

(October 11-12) - Recording of part of Handout #13, PowerPoint notes outline on momentum.   

There are two types cof collisions: elastic & inelastic.

The concept of a system was also introduced.  In this case, the system involved the Mystery Machine van and a red car.

(9) MOMENTUM (3) Elastic Collisions

(October 11-12)  - Say hello to Felecia.  

The Conservation of Momentum was (hopefully) reinforced when showing with math that momentum is not lost in a collision -- it just gets transferred within the system (between Freddy's MMS Donut truck and  Felecia's green sports car).  

(6) SKYDIVER & TERMINAL VELOCITY

(October 8-9) - So, a skydiver jumped out of a perfectly good airplane.  Let's follow her down to the ground and identify at what point she was accelerating and why she was accelerating.  What is acceleration, anyway?  It is important to wrap your minds around the concept of balanced forces and unbalanced forces.  Got it?  Newton's first law mentions the term "unbalanced forces".  So, what does that really mean?  

Big idea --> In order to change an object's velocity, an unbalanced force must be acting on that object.

Discovery Channel video link

(7) MOMENTUM (1)

(October 11-12) - Recording of Handout #13, PowerPoint notes outline on momentum.   Momentum is best described as mass in motion.

So, what is momentum?  What are its units and how do we calculate it?

(5) Dave Sticks His Landing

(October 6) This was Station 5 in our Laws of Motion Lab.  Did Dave and his cart meet an unbalanced force?  His cart did, but as for Dave . . . 

(3) Newton's 2nd Law of Motion

(October 10-11) - Newton’s 2nd law of motion states:

F = m x a

(4) Newton's 1st Law of Motion

(October 10-11) - Newton’s 3rd law of motion states:  For every action there is an equal and opposite reaction.  

(1) Forces

(October 4-6) A force is a push or pull that causes an object to change its velocity.  Remember that an object's velocity is its speed + its direction.  Velocity is a vector.  A car travelling at 65 mph is not considered to have velocity.  Speed?  Yes.  In order for that car to have velocity, it must have a direction assigned to it.  How about this?  A car travelling 65 mph south has velocity becuause it has both speed and direction.  

(2) Newton's 1st Law of Motion

(October 10-11) - Newton’s three laws of motion form the foundation for classical mechanics.  Classical mechanics is the branch of science dedicated to objects in motion and the forces that affect them.  

The objects in motion could be large bodies such as our moon orbiting (circling) the earth.  It could even be larger things like our solar system orbiting the center of its galaxy (the Milky Way).  They could also be ordinary objects such as a moving car or a model rocket launched from Memorial Park here in Maplewood.  

Even bodies at rest are considered in motion.  Bodies at rest?  Sleeping?  No, bodies are objects.  ‘At rest’ refers to objects that are not moving.  They are objects with zero velocity.  A parked car is a body at rest.  It has zero velocity.  This sounds really weird, but it is part of the language of physics.