I created this simulation for use later this semester with my IP4 classes, to illustrate the concept of phase difference between two oscillating particles.

## Using a mobile phone in a petrol station.

So it's safe to use a mobile phone in a petrol station. But not wearing nylon.

For more on this, read the Straits Times article : http://www.straitstimes.com/asia/se-asia/use-of-mobile-phones-at-petrol-stations-do-not-cause-fires-experts

## Explanation for Water Bending with Static Electricity

It's interesting to note the differing views regarding the explanation for how a thin stream of water can get bent when a charged object is placed near it. It started with these two videos from Veritasium:

This video then sets out to disprove Veritasium's model of ions being removed from the water stream.

## Simulation for Gravitational Field Strength and Potential

This simulation allows students to observe the variation of gravitational field strength and potential between two masses. Field strength is shown as vectors whereas potential is shown as scalar values on a plot. The resultant field strength and potential are shown in red.

## Falling with Parachute

The following simulation allows users to observe the effect of air resistance on a parachutist before and after he opens his parachute. Try to open the parachute when the man first reaches terminal velocity and observe the changes in velocity.

## Box on a Slope Simulation

This simulation allows students to observe the variation of the normal contact force **N** acting on a box placed on a *frictionless slope* with the angle of inclination of the slope changing. It also allows them to see how the Weight vector **W** can be resolved into two components, with the one perpendicular to the slope being equal at all times to **N. **Meanwhile, the component of **W** parallel to the slope being proportional and in the same direction as acceleration.

## Man in Elevator Simulation

In this simulation, students can observe the variation of the normal contact force (N) and its effect on acceleration and velocity as an elevator moves upward.

Questions for students to work on can include:

- Express the acceleration as a function of Normal Contact Force (N), Weight (W) and mass of the man.
- Determine the distance travelled by the elevator.
- Predict how the forces, acceleration and velocity will differ if the elevator was moving down instead.

## Internal Resistance and Maximum Power Theorem

I've created this simulation to demonstrate the effect of an internal resistance due to a cell on the potential difference and current of an external load.

One can also vary the internal resistance and external resistance to observe the maximum power theorem. The theorem states that for a given finite internal resistance, one can obtain the maximum external power only when the resistance of the load is equal to the internal resistance of the source.

## Variable Resistor Simulation

My third simulation in as many days. This time round, I created some png files for electrical circuit components that can be used for future simulations. I also figured out how to add text in line with a variable in the drawing panel for the simulation, hence the units can now follow the values of the meter readings.

## Simulation for Potentiometer

Continuing the course on Easy Java Simulation, I did this simple simulation on the Potentiometer, which allows students to first predict, and then verify the position of a jockey to achieve null deflection of a galvanometer.

Click on the image below to try it out and do give me your feedback. I'll try to improve it with whatever little skill I have.

I decided on a DC circuit simulation as I could not find many on Open Source Physics EJSS platform. With this as a template, I guess I can develop more simulations on the same topic when I have time.