Answer:
At least (3 significant figures.)
Assumption: there's no air resistance.
Explanation:
Let be the minimum speed at which that salmon leaves the water with an elevation angle of . .
- Initial horizontal velocity: ;
- Initial vertical velocity: .
Why is the initial horizontal velocity important? If there's no air resistance, the horizontal velocity of the fish will stay the same during its flight.
By the time the fish reaches the upper rim of the waterfall, it would have traveled horizontally. How much time after take-off will that occur?
.
For the fish to continue upstream, its height should be at least by the time it reaches the upper rim of the waterfall. In other words, at , .
If there's no air resistance, on the vertical direction the fish would accelerates downwards at a constant during the entire flight. Its height could be expressed as
.
That's the same as:
.
Let , Solve this equation for
.
Given that , .
In other words, the fish must leave the water at a speed of at least to continue upstream.
Answer: i believe its chemical change or thermal depends on the question answers
using the law of refraction, the incidence is equal to the reflection, but not refraction
The two most common ways are the use of a water restrictor in the shower head, most of the heads in the U.S.A are equipped with a water restrictor. Secondly, the commode water tanks have been made smaller using less water per flush. Some conservation of water may be gained by using "instant" water heaters in the shower/bath and basin rather than a hot water tank type heater. Locating an instant water heater near the output of the water reduces the need to let the water run until it becomes hot at the output. I hope that this is the answer that you were looking for and it has helped you.