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Describe the changes in forces experienced by a parachutist after they have started falling

Initially, the parachutist will experience a greater downwards force due to gravity which causes them to accelatae downwards. As they accelarate, the upwards force of air resistance will increase. They will ...
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Answered by Iona N. • Physics tutor
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What is the difference between a scalar and a vector?

A quantity that has magnitude (size), but no direction, is a scalar. A quantity that has magnitude (size) AND direction is a vector. Scalar quantities just have a magnitude. The direction does not matter. Ex...
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Answered by Alex V. • Physics tutor
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Calculate the acceleration of particle thats velocity changes from 20ms^-1 to 40ms^-1 in 5 seconds, assuming its constant.

Acceleration is the rate of change of velocity, so we subtract the final velocity from the initial velocity and divide it by the time taken for the change. In this case the acceleration is (40-20)/5 = 4ms^-2...
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Answered by Orlando F. • Physics tutor
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What is the name given to waves where the oscillations are in the same direction as the wave energy?

When the oscillations of the waves are parallel to the wave energy, we call the wave longitudinal. An example of a longitudinal wave could be s ound waves.
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Answered by Rifat M. • Physics tutor
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An atom can become excited by the absorption of photons. Explain why only photons of certain frequencies cause excitation in a particular atom.

Electrons in an atom occupy discrete energy levels. An electron can only be excited to another level if it absorbs the exact amount of energy as the difference between the two levels. Therefore the energy of...
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Answered by Arinjay J. • Physics tutor
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