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:
The potential for r > rb is equal to zero.
Explanation:
For r > rb, the potential is:
Then, the net potential is:
According to our principle, when an object is slowing down, the acceleration is in the opposite direction as the velocity. Thus, this object has a negative acceleration. ... When an object is speeding up, the acceleration is in the same direction as the velocity. Thus, this object also has a negative acceleration.
Answer:
The distance that the racecar traveled is indeed 500m. But at the end of the lap, it is right back where it started. So overall, it has been displaced 0m.
Explanation: