LVang+-+Lab+9+-+Physlets+exp(3.2,+4.2,+4.3),+illus(3.2)

__**Physlets Entry #2**__

__Exploration 3.2__

Data: Position Control = 4.6s (0.05s with cheats) Velocity Control = 3.8s Acceleration Control = N/A (Test is not doable in the allotted 30 minutes)

Analysis: a.) Yes, it is possible to navigate to the goal on the right for all the controls, but the experiment subject is only able to do so with two, the position and the velocity controls.

b.) The acceleration control is the hardest to use probably because it has the most complex vector. For example, position is a scalar dimension so it's the easiest control because the conductor only worries about one quantity. Velocity gets harder as the number of quantity increases to two, and the conductor must worry about the constant change of motion in the ball. Finally, acceleration adds in the worry of how fast the motion is changing, thus making it the hardest control to manage.

__Exploration 4.2__

When the ball is placed vertically centered between the two points of attraction and its horizontal position is skewed to the left or right, the ball will move in a straight line towards the point in between the two points of attraction. This happens because both points all pulling the ball to themselves. The force vector of each point of attraction is diagonal, but the vertical component of each one's vector cancel out, leaving only the horizontal force to pull the ball horizontally. Eventually, the force pulling will be so great that the net force makes the ball pass the center. Once it does, the two points of attraction will diminish the net force of the ball's original direction and change it to pull the ball in the other direction, but the net force will be so great that the ball passes the center again and the cycle repeats.

When the same setup is put into repulsion mode, the ball is pushed directly horizontal towards the edge of the play area. Again, this is because the vertical components cancel out, leaving only the horizontal component in effect towards the net force. Once the repulsion sends the ball and makes it hit the wall, the wall sends an equal and opposite reaction on the ball, sending it back where it came. When the ball its close to the two points of repulsion, the ball slows down because the force of repulsion gradually diminishes the force of the ball moving towards to the two points of repulsion. Eventually the net force diminishes so low that it'll change direction, sending the ball back towards the wall and the cycle repeats.

__Exploration 4.3__ a) In attraction mode, the task is done in 2.14 seconds. In repulsion mode, the task is done in 1.06 seconds.

b.) With an applied force, the ball moves with a net force of its original trajectory and the applied force. Applying a force in the direction of its the ball's original trajectory will result in an acceleration and vice versa. c.) The way does not always move in the way expected because it is accelerating, constantly changing its velocity, making its movements hard to predict. Also, the vector's of the net force's trajectory are composed of both (x) and (y) components, so it's harder to mentally calculate the change in net force.

__Illustration 3.2__ Galileo found the change in velocity. The displacement increase in odd integers indicate that the actual amount of displacement is a positive number, specifically 2 meters.

In the relationship between displacement in time, the total displacement is the square of the elapsed time as it should be Δ x is proportional to t ² according to the kinematic equation x = x0 + v0*t + 0.5*a*t2.