What are two ways to change the state of a substance

How many seconds does it take a pebble released from rest off a bridge to fall 29.4 m ? what is the pebble's speed when it has fallen 29.4 m ?

What must be the same for any two resistors that are connected in series ? a. the potntial diffrence across each b. the rate at which charge moves through each c. the rate at which energy is used by each d. the resistance to the flow of charge of each

Arod of some material 0.20 m long elongates 0.20 mm on heating from 21 to 120°c. determine the value of the linear coefficient of thermal expansion [in (degrees c)^-1] for this material.