Astone is thrown directly upward with an initial speed of 9.6 m/s from a height of 12.8 m. after what time interval (in s) does the stone strike the ground? use g 9.8 m/s^2 enter a number with 2 digits behind the decimal point.

Oxygen and hydrogen gas are at the same temperature t.what is the ratio of kinetic energies of oxygen molecule and hydrogen molecule if oxygen is 16 times heavier than hydrogen.

Aperson walks first at a constant speed of 4.89 m/s along a straight line from point a to point b and then back along the line from b to a at a constant speed of 2.95 m/s. what is the average speed over the entire trip?

1) what is the power in horsepower of a 100 watt light bulb? what is the power in kilowatts of a 200 horsepower engine? 2) if a cars engine is providing 3000 n of force to keep the car moving at 5 m/s, what is the engine’s effective power? 3) how many gallons of water will be pumped from a well 30 feet deep by a 1/2 hp engine in 1 minute? (1 gallon weighs 8.34 pounds)