Physics questions

Textbook pg 72 # 54, 56, 58, 60, 62, 63

aerodynamic egg glider

I think a good design for an egg glider would be to use the 25 straws to make a skeleton of the glider. Then cover the skeleton with newspaper so that air can be trapped, slowing the glider's fall. The skeleton would have 2 wings like a bird. Then loosely cover the wings with newspaper leaving room for air to accumulate. A central compartment would be designed to hold the egg. This protects the egg from all sides so that when the glider reaches the ground, the egg won't break or anything. It would be located in the middle of the glider so the centre of gravity is balanced across the whole structure. When it is thrown off the school, the wings will catch air and slow the decent. The glider will float to the ground, acting as a parachute for the egg and preventing it from breaking.

5 results from walking graphs + translations

 1

This was the first graph we walked and it mapped distance. Therefore, the higher the line is on the graph, the farther we go from the motion detector. A straight line means we stand still and decreasing/increasing lines means going closer or farther from the detector. So, we start at 1m away from the detector, and walk 2.8m away from the detector in 3 seconds. Then stand still at that spot for 3 seconds. Then walk back to 1.8m away from the detector in 1 second. Then stand still for 3 more seconds.

This is the second graph we walked, also in distance. We start at 3m away from the motion detector and move to 1.5m away from the detector in 3 seconds. Then stand still for 1 second. Then walk 0.5m away from the detector in 1 second. Stand still for 2 seconds. Then walk back to the origin of 3m in 3 seconds. However, our group did not stand at the exact spots and it got messed up at the end.

This graph calculated velocity and was probably the hardest one we attempted. Basically, vertical lines indicates the direction and the speed at which you go in that direction. Horizontal lines mean keep a constant speed. Start by standing still for 2 seconds. Then walk backward at 0.5m/s in less than a second. Keep walking backward at 0.5m/s for 3 seconds and then stop for 2 seconds. Walk in the other direction at 0.5m/s and maintain that speed for 3 seconds. This was extremely hard as keeping a constant speed was very difficult.

Another velocity graph which was as difficult as the last one. Start moving backward increasing speed as you walk peaking at 0.5m/s for 4 seconds. Stay at the peak speed for 2 seconds. Go forward at 0.5m/s in 3 seconds. Move backward decreasing speed until standing still in 1 second.

The last graph which mapped distance. Start a little less than 1m away from the detector and go to 1.9m away in 3.5 seconds. Stay at that location for 4 seconds. Then walk backward to 3.2m in 3.5 seconds.

Walking the graph lab

Today, our class changed rooms and did the "walking the graphs" experiment. We were split into groups and each got a laptop and motion detector. Then we opened preset graphs to walk them. Most were motion graph where the motion detector detected our movements and plotted it next to the onscreen graph. We were supposed to match the motion preset graph as closely as possible.
Heres our first attempt at the first graph (b):

As you can see, we were pretty close!
Some graphs werent as simple however. For example, we got a graph that plotted velocity. Walking at a constant speed was difficult, and then changing to a higher speed fast was even more hard.
Heres our attempt:

its pretty bad, but it was extremely hard.

Right Hand Rule 1 + 2

The Right hand rules are used to determine the direction of current and the north and south poles of a conductor or coil. The Right hand rule literally uses your right hand to measure these things. With a conductor, you wrap your right hand around it and bend your fingers in, similar to a 'cat'. The direction in which your thumb is pointing is the direction of the flow of current. The fingers symbolize the invisible magnetic field around the conductor.

This is known as the Right hand Rule.

Concept Mapping

Today, our class experimented with a new method of learning called "Concept Mapping". Instead of writing down notes, you link ideas together with verbs in a sort of web. This is our groups concept map:

The title "electricity" is placed in the middle with different ideas such as "ohm's law" and "kirchoff's law" linked to it. Then, there are links to similar subjects with verbs. For example, voltmeter is connected to volts with the verb " measured with".

       10 things to know for this unit:
1. Ohm's Law
- The VIR triangle
2. Kirchoff's Law
- All the formulas for calculating voltage, current, and resistance in series and parallel circuits
3. e= 1.6*10^-19 C
4. Current = Q/t
-Q is coulomb charge
- t is time in seconds
5. How to draw / understand circuit diagrams
- resistor symbol
- power source symbol
- where the ammeter and voltmeter goes
- ability to identify series from parallel circuits

Ohm Vs. Kirchhoff

Ohm's law states that voltage has direct relation to current. When voltage is high, so is the current and vice versa. Also, resistance is stays the same in different circuits. These concepts can be explained by the simple formula : V=R*I. One can easily remember this formula by drawing a triangle, placing V at the top and R and I on the bottom.

Kirchhoff's law is used for complex circuits and uses lots of formulas that correspond to either series circuit or parallel circuit to determine current, voltage, and resistance. In a series circuit, current (I) can be expressed as I(t) = I(1) = I(2) = I(3) =...=I(n). This means that throughout a series circuit, the current stays constant. In a parallel circuit, current is expressed as I(t) = I(1) + I(2) + I(3) +...+I(n). The current in a parallel circuit is the sum of all the loads' currents.
Voltage, in a series circuit, is expressed as V(t) + V(1) + V(2) + V(3) +...+V(n). In a parallel circuit, voltage is expressed as V(t) = V(1) = V(2) = V(3) =...=V(n). However, resistance is a bit different. In a series circuit, resistance is calculated as R(t) = R(1) + R(2) + R(3) + ...+R(n). In a parallel circuit, resistance is expressed as 1/R(t) = 1/R(1) + 1/R(2) + 1/R(3) +...+ 1/R(n).