March 1, 2010

Today, we watched a video about momentum. We were told to write down 5 to 7 points about momentum and hand it in at the end of the period. If you weren't paying any attention to the video, "momentum is inertia in motion". Momentum is also the product of mass and the velocity (momentum = mv). Onward, "impulse" occurs as force is applied to an object over a period of time (impulse = Ft). As said in the video, impulse is also equivalent to momentum. Which, would be expressed as: Ft = mv.

Further into the video, the guy showed a few examples to give a visual image to better understand the concept. He used this train thing that shoots air to allow the pieces of metal to lie on a cushion of air to simulate a near frictionless surface.

Anyway, on the train thing, he showed object A collide with object B; object A ceased while object B continued forward. He continued to explain that momentum is conserved in collisions. The guy went on about object B having an impulse at the opposite direction when the two objects collided. Which canceled out the momentum of object A (putting it to a stop) while the conserved momentum allowed object B to continue moving on. Another example of this would be Newton's Cradle (the thing with the balls bouncing).

Another example on the train thing was when he showed that object A would stick to object B when colliding with each other. Object A travelled towards object B along the track, and when colliding (and attaching to object B), the same inertia is maintained from the initial momentum of object A travelling by itself. As a result, the attached objects A and B travelled at a slower speed than the velocity of what object A initially had. The guy explained that the momentum is the same, because the mass doubled and the velocity changed in proportion (Δmv = same momentum) .

I apologize if this is a bit confusing. Anyway, Ms. K didn't give our tests back yet... although, feel free to ask her what your score is.

Next scribe is Sayana! Good luck.