a train travels 81 kilometers in 2 hours and then 88 kilometers in 2 hours what is its average speed

An electron in the first energy level if the electron cloud has lower higher or the same energy as an electron in the third energy level

The maximum wavelength of light required to eject an electron from zinc is 270nm. Calculate the threshold frequency of zinc.

Sanitation can be accomplished by all of the means except

A fishing boat drags a net for 25 seconds, doing 3500 Joules of work. How much power was the boat using?

Adiabatic Equation of State Derive the adiabatic equation of state (2.3.19) using particle conservation (2.3.7) and energy conservation (2.3.21), by assuming that the heat flow vector q and all collision terms in these equations are zero.

What causes day and night on earth?

A yo-yo can be thought of as a solid cylinder of mass m and radius r that has a light string wrapped around its circumference (see below). One end of the string is held fixed in space.

Why is time an independent variable and position is a dependent variable in a position versus time graph

A geologist estimates that a large boulder weighs 7840 N. What should he estimate the mass of this boulder to be? A. 650 kg B. 740 kg C. 780 kg D. 800 kg

Two objects have the same momentum. Do the velocities of these objects necessarily have (a) the same directions and (b) the same magnitudes? Give your reasoning in each case.