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The Doppler effect describes the changes in a wave's frequency (or wavelength) as the source of the wave moves towards/ away from the observer (you). You have almost definitely experienced this phenomenon be...

First it's important to remember that a wave isn't an object that is moving. When a wave moves through a substance the particles of the substance move side to side or backwards and forwards around their orig...

When an object falls down through a fluid (e.g. water, oil, air..) there are usually two forces acting on it. They are the weight force acting downwards and the drag force acting upwards. The weight force co...

When the balloon is rubbed on your head, it becomes electrostatically charged (this is because electrons are transfered to/from the balloon from/to your hair). When you bring the balloon, which now has an ex...

Terminal velocity occurs when an object in free fall doesn't accelerate any further. As F=ma, when a = 0, F must be 0. F in this equation refers to resultant force. Because all objects in earth's gravity hav...