This aeroplane has an electric motor powered by fuel cells. Fuel cells use hydrogen gas and provide an electric current.
(a) When the aeroplane is working, the energy changes are
ZA chemical - electrical - kinetic
2 B electrical --> chemical - kinetic
DC electrical kinetic chemical
D kinetic - Chemical electrical

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.

Why does lightning travel from clouds to the ground?

What part of the ear is names after tools, such as the hammer and the anvil?