Work = (force) x (distance)
Each time she lifts the weight, she does
(550 N) x (0.5 m) = 275 joules of work against gravity.
Each time she lets the bar down gently, gravity does
(550 N) x (0.5 m) = 275 joules of work against her muscles.
If the human physical muscular system were 100% efficient, and capable
of absorbing work as well as spending it, then the bodybuilder would do
exactly zero work in the process of 1-up followed by 1-down.
Answer:
Vs/c = 20 [m/s]
Explanation:
This is a problem of relative velocities, as velocity is a vector we can use addition or subtraction of vectors for the solution.
We are asked for the velocity of the sailboat with respect to an observer located in the canoe.
Why is the speed of the canoe negative?, it is negative because the canoe moves in the opposite direction to the sailboat.
Answer: Taking into account sound is a wave, we can use the information of the displacement (generally given as a graph) to find the wavelength and frequency, then we can calculate the speed with the formula of the speed of a wave.
Explanation:
If we have the displacement graph of the sound wave, we can find its amplitude, its wavelength and period (which is the inverse of frequency).
Now, if we additionally have the frequency as data, we can use the equation of the speed of a wave:
Where:
is the speed of the sound wave
is the wavelength
is the frequency