The yo-yo speeds up when you rub it
Hello this is to other people looking for the answer. Everyone else is wrong. I just took the quiz on e2020. The answer actually Comparative. Your welcome. Have a nice day.
Answer:
x = 6.94 m
Explanation:
For this exercise we can find the speed at the bottom of the ramp using energy conservation
Starting point. Higher
Em₀ = K + U = ½ m v₀² + m g h
Final point. Lower
= K = ½ m v²
Em₀ = Em_{f}
½ m v₀² + m g h = ½ m v²
v² = v₀² + 2 g h
Let's calculate
v = √(1.23² + 2 9.8 1.69)
v = 5.89 m / s
In the horizontal part we can use the relationship between work and the variation of kinetic energy
W = ΔK
-fr x = 0- ½ m v²
Newton's second law
N- W = 0
The equation for the friction is
fr = μ N
fr = μ m g
We replace
μ m g x = ½ m v²
x = v² / 2μ g
Let's calculate
x = 5.89² / (2 0.255 9.8)
x = 6.94 m
516.154 megawatts of heat are <em>exhausted</em> to the river that cools the plant.
By definition of energy efficiency, we derive an expression for the energy rate exhausted to the river (), in megawatts:
(1)
Where:
- - Efficiency.
- - Electric power, in megawatts.
If we know that and , then the energy rate exhausted to the river is:
516.154 megawatts of heat are <em>exhausted</em> to the river that cools the plant.
We kindly to check this question on first law of thermodynamics: brainly.com/question/3808473