Two particles, an electron and a proton, are initially at rest in a uniform electric field of magnitude 478 N/C. If the particles are free to move, what are their speeds (in m/s) after 52.4 ns

An inclined plane wrapped around a metal shaft is a a. lever b. screw c. pulley d. wedge

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? question 2 options: the balloons rise at the same rate. both balloons are the same size. the ballons both rise. the cold ballon is larger than the warm balloon. the cold balloon expands and rises. the warm balloon shrinks and sinks. the warm balloon expands and rises. the cold balloon shrinks and sinks.

If the chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?