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What is the mass of an object travelling at 15 m/s with a kinetic energy of 100 J?

Kinetic Energy (E k ) = 1/2(mv 2 ).This can be rearranged such that, m = (2E k )/v 2 we know from the question that E k = 100 J and we know that v = 15 m/sso plugging in the numbers, we get m = (2 x 100)/(15...
TD
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What's the difference between distance and displacement

Distance is a scalar, meaning it only has a magnitude. Displacement is a vector, meaning that it has both magnitude and direction. For instance, distance can state that I am "x" metres away from a ...
EG
Answered by Emma G. • Physics tutor
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What is the De Broglie wavelength of an electron given it has a kinetic energy of 1 eV? You are given the mass of an electron is 9.11x10^-31 kg and Planck's constant is 6.63x10^-34

The De Broglie wavelength equation is as follows: λ=h/p We know the value of Planck's constant h and so to calculate the wavelength all we need is the momentum, which is equal to mv. The kinetic energy is gi...
DM
Answered by David M. • Physics tutor
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If the highest frequency a song is 10 kHz and it is encoded at 16 bits per sample what is the minimum number of bytes needed to encode the 3 minute song?

The key to this question is to remember the Nyquist rate of a signal. This is the lowest sample rate which can be used for a signal without losing valid frequencies or gaining incorrect frequencies. This is ...
DM
Answered by David M. • Physics tutor
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When red light is shone on a metal, regardless of the intensity of this light, no current will flow. However if blue light is shone on this metal a current will flow. Why does this occur?

This problem can be solved by first considering the energy of a photon e = hf. ​A photon of red light lacks the sufficient energy to free an electron. However a photon of blue light has a higher frequency an...
JP
Answered by Jonathan P. • Physics tutor
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