Why are symbols used in circuit diagrams

Agroup of students were investigating the force of gravity. they began by dropping a foam ball from a height of 3 meters into a bucket of sand. the ball hit the sand in 0.306 seconds. they dropped additional balls of approximately the same diameter, but of different masses. here is the data they collected. based on this experiment and the collected data, what would their conclusion be?

When you hold a rectangular object, how does the area of the side that is resting on your hand affect the pressure and the force that the object exerts?

How can you measure the amplitude of a longitudinal wave?