An elephant kicks a 2.5 kg rock that is initially at rest. The net force on the rock varies with time as shown below.
What is the rock's change in momentum between 0 ms
and 20 ms?

Hydrogen and helium are both members of?

Explain what happens at the saturation point when adding salt to water at room temperature.

A10nc charge sits at a point in space where the magnitude of the electric field is 1500 n/c. what will the magnitude of the field be if the 10 nc charge is replaced by a 20 nc charge? assume the system is big enough to consider the charges as small test charges.