Momentum

Momentum is simply the mass of an object multiplied by its velocity.

M=m(v)

Momentum can be changed through impulses and by how long the impulse lasts.

Impulses increases when an object bounces, this is because technically, bouncing consists of many impulses, and when they are all put together the overall impulse Is larger than an object tha tdidnt bounce.

Impulse Lab

The slope of this graph proves that impulse and the change in velocity are directly related. It also gives us an equation for impulse which is

Impulse=mass(change in velocity)

In the Collision lab we had a car with two springs on it. One with a plunger and one with a large circular spring on the front.

We measured force exerted by the car and the spring with a force detector and we measured position with a motion detector.

The oval spring had a smaller force than the plunger but the force exerted by the oval spring longer than the force exerted by the plunger.

We later called this the impulse, which was the same, the only difference was the time it took to exert the force.

Impulse = F * t

Impulse is related directly with mass

In the second lab we had two cars on the same ramp. One was not moving in the center of the ramp and the other we ran into the stationary car. We measured the velocity before, the velocity after, change in velocity, impulse, momentum before, and momentum of both after. Today (Feb. 4th, 2010) we decide in class what sets of data we need to graph in order to come up with anther model to find dissipated enegy.

Formulas we have so far:

Impulse = m * (change in) v

mv = p [mass * velocity = momentum]

current model

In class we discussed our data and developed our model. We determined that the relationship between force and energy is indirect. In other words when net force goes up energy goes down. After looking at the trend lines from the data we decided that the equation (F=21/d). however, we were able to reform this into a more applicable equation and the end result which is our current model is F(D)=21

rotation

Rotation is very similar to linear movement in the sense that the laws of motion and inertia still apply. For example we discussed in class whether or not the skater was applying a force mid spin. We determined that the skater was not applying force at the time of the spin but instead was relying on the laws of inertia to aid her in her task. Over time even with the most minute amount of friction the rotation will slow and eventually cease. However the rotational movement differs from the linear movement at one key point. The rotational movement doesn't change position.

Air pressure, spin, and curve balls

Bernoulli's principle that states if air on one side of an object moves faster than the air on the other side, that the air on the side of the slower air will create a "push" while trying to equalize the pressure by getting to the other side. This is why planes get lift, curveballs curve, and why the roof of your house gets blown off in a wind storm. Athletes such as baseball players know that spin is essential in changing the trajectory of an object. This is because when spin is created the air automatically moves faster on one side of the ball creating a push and throwing the ball off a straight trajectory.

From the paper ball toss lab that we completed in class, we determined that Air resistance is a form of friction. And like friction when it was applied to the ball while it was in flight the ball no longer flew at a constant horizontal velocity. Also the parabola relating to the ball's vertical velocity was steeper as the paper ball returned to earth.