Answer:
frequency = 5.52 * 10² Hz
Explanation:
the equation that relates velocity, frequency and wavelength is:
velocity = frequency * wavelength
We are given that:
velocity = 331 m/sec
wavelength = 0.6 m
Substitute with the givens in the equation to get the frequency as follows:
velocity = frequency * wavelength
331 = frequency * 0.6
frequency = 331 / 0.6
frequency = 5.52 * 10² Hz
Hope this helps :)
Answer:
1081.9 J
Explanation:
In order to calculate how much energy is converted into thermal energy due to friction, we have to calculate the difference between the mechanical energy of the child at the top and at the bottom of the slide.
At the top of the slide, he is at rest, so its kinetic energy is zero, and so he only has gravitational potential energy. Therefore:
where
m = 24 kg is the mass of the child
g = 9.8 m/s^2 is the acceleration of gravity
h = 5 m is the height relative to the ground
At the bottom of the slide, the child has only kinetic energy, so its total energy is
where
v = 2.8 m/s is the final speed of the child
Therefore, the therma energy generated due to friction is equal to the difference between the initial and final energy:
Work = (force) x (distance)
80 J = (force) x (4 m)
Force = (80 J) / (4 m) = 20 N
That's IF the force was in the same direction as the 4m of motion.
If the force was kind of slanted, then it had to be stronger, and
it had a component of 20N in the direction of the motion.