Salmon often jump waterfalls to reach their breeding grounds. starting downstream, 2.33 m away from a waterfall 0.488 m in height, at what minimum speed must a salmon jumping at an angle of 38 ◦ leave the water to continue upstream? the acceleration due to gravity is 9.81 m/s 2

5.68 m/s

Explanation:

The motion of the salmon is the same as a projectile: it is launched with an initial speed at an angle of above the horizontal.

The motion of the salmon consists of two indipendent motion:

- Along the horizontal direction, it is a uniform motion with constant velocity

So that the distance travelled is

(1)

- Along the vertical direction, it is a uniformly accelerated motion with constant acceleration downward, so the vertical displacement is

(2)

where g is the acceleration of gravity.

We know the following:

- The horizontal distance travelled by the salmon to reach the waterfall is

d = 2.33 m

- The vertical distance travelled is the height of the waterfall,

y = 0.488 m

From (1) we get:

And substituting into (2), we can solve the equation to find t, the time at which the salmon reaches the waterfall:

And then, we can use eq.(1) again to find the initial speed, u:

weather forecasts are done by collecting data about the current state of the atmosphere mainly the temperature, humidity and wind and using meteorology, to determine the atmosphere that evolves over time. the h and l mean the high and low pressure. the red strip is a warm front. the blue strip is a cold front. the blue and red strip is a stationary front. the purple strip is a occluded front.

explanation: