A student is hit with a 1 kg pumpkin pie. The kinetic energy of the pie 32 J. What was the speed of the pie?
1 answer:
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Answer:
4.1 eV
Explanation:
Kinetic energy, K = 0.8 eV = 0.8 x 1.6 x 10^-19 J = 1.28 x 10^-19 J
wavelength, λ = 253.5 nm = 253.5 x 10^-9 m
According to the Einstein energy equation
Where, E be the energy incident, Wo is the work function and K is the kinetic energy.
h = 6.634 x 10^-34 Js
c = 3 x 10^8 m/s
So, the work function, Wo = E - K
Wo = 7.85 x 10^-19 - 1.28 x 10^-19
Wo = 6.57 x 10^-19 J
Wo = 4.1 eV
Thus, the work function of the metal is 4.1 eV.
If the tension in the rope is 160 n, - 43200 J work doen by the rope on the skier during a forward displacement of 270 m.
Given,
Tension force in the rope is (T) = 160 N
Displacement of the skier (S) = 270 m
The displacement takes place in forward direction while the direction of the tension in the rope is opposite to it.
Therefore, work done by the rope on the skier is,
⇒
Hence work done by the rope is - 43200 J.
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