Salmon often jump waterfalls to reach their breeding grounds. starting 3.15 m from a waterfall 0.45 m in height, at what minimum speed must a salmon jumping at an angle of 33.2 degree leave the water to continue upstream? the acceleration due to gravity is 9.81 m/s2. answer in units of m/s.

How would you place two electrons on a sphere of radius r so that the electrostatic potential energy is minimized. how would you place three electrons to solve the same problem.

Unpolarized light falls on two polarizer sheets whose transmission axes are at right angles. a third polarizer is placed between the first two so that its axis makes a 52-degree angle with the axis of the first polarizer. a) what fraction of the incident light intensity is transmitted through the first polaroid? b) what fraction of the incident light intensity is transmitted through the second polaroid? c) what is the angle of polarization of the light that enters the third polaroid? d) what fraction of the incident light intensity is transmitted through the third polaroid. e) what happens if the middle polaroid is removed?

If a tank filled with water contains a block and the height of the water above point a within the block is 0.8 meter, what is the pressure at point a?