Final answer:
Hand signals in physics include the right-hand rule for angular velocity and angular momentum, and the left-hand rule for determining the magnetic force's direction on a moving charge. In everyday context, an 'L' shape usually signifies turning left, a straight arm signals right, and a downward turn of the arm can indicate stopping or slowing down.
Step-by-step explanation:
Hand signals are used in various contexts, such as cycling, driving, and in physical sciences to represent different concepts. For instance, the right-hand rule is a common mnemonic in physics that relates to the direction of angular velocity (w) and angular momentum (L). To use the right-hand rule for determining the direction of angular velocity or angular momentum, extend your right thumb and curl the rest of your fingers. Your thumb points in the direction of the angular velocity or angular momentum, while your fingers curl in the direction of the disk's rotation.
Similarly, the left-hand rule is employed in electromagnetism to determine the direction of the force when a charge moves in a magnetic field. Here, you line up your thumb with the positive x-direction (representing velocity), and let your fingers point into the page (indicating the direction of the magnetic field), showing the resulting magnetic force direction is downward.
In terms of simpler signals used in day-to-day life, a hand signal that looks like an 'L' typically indicates a left turn on a bicycle or in a car where turn signals might not be visible. A straight horizontal arm would generally indicate a desire to move or turn right, and an arm pointing downward could indicate stopping or a decrease in speed.