Answer:
20 m/s
Explanation:
The speed of a wave is given by:

where
is the wavelength
f is the frequency
v is the speed
For the wave in this problem,
f = 10 Hz is the frequency
is the wavelength
So the speed is

Answer:

Explanation:
We have,
The surface temperature of the star is 60,000 K
It is required to find the wavelength of a star that radiated greatest amount of energy. Wein's displacement law gives the relation between wavelength and temperature such that :

Here,
= wavelength

So, the wavelength of the star is
.
Answer:
the work that must be done to stop the hoop is 2.662 J
Explanation:
Given;
mass of the hoop, m = 110 kg
speed of the center mass, v = 0.22 m/s
The work that must be done to stop the hoop is equal to the change in the kinetic energy of the hoop;
W = ΔK.E
W = ¹/₂mv²
W = ¹/₂ x 110 x 0.22²
W = 2.662 J
Therefore, the work that must be done to stop the hoop is 2.662 J
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