# Physics help

1. Aug 27, 2004

### Hollyleelee

hi everyone! ok so i was doing my homework and i came upon this one problem which completely stummped me and so if someone could set me in the right direction i would be very thankful! here is the promblem: If a salmon swims sraight upward in the water fast enough to break through the suface at a speed of 5 meters per second, how high can it jump above water?

2. Aug 27, 2004

### cepheid

Staff Emeritus
Its initial velocity is 5m/s. This will steadily decrease because it is acted upon by constant acceleration g. Figure out using the kinematic formula for velocity as a function of time (with constant accleration) how long it will take for its velocity to become zero (in mid air). And then, use this time in the formula for the height of the salmon as a function of time to get the maximum height it reaches.

3. Aug 27, 2004

### Chronos

Pretty straight forward. Assume it jumps straight up out of the water [90 degrees]. Next apply the gravitational constant [9.8 meters/sec^2] and do the math.

4. Aug 27, 2004

$$V^2 = {V_o}^2 + 2ad$$
$$\frac{-{V_o}^2}{2a} = d$$