What is the force of gravity acting on a 40.0 kg object located on the earth's surface?

Frost wedging occurs when water seeps into a crack in a rock, freezes, and causes the crack in the rock to widen. t or f

The weights of bags filled by a machine are normally distributed with a standard deviation of 0.05 kilograms and a mean that can be set by the operator. at what level should the mean weight be set if it required that only 1% of the bags weigh less than 9.5 kilograms? round the answer to 2 decimal places.

Awave has a wavelength of 7 mm and a frequency of 19 hertz. what is its speed?