A man of mass 80kg carries a load of mass 20kg up a vertical ladder of length 6m. what work has he done (Take g= 10ms-2)​

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.

The charge on a charged sphere is: a)concentrated at its centerb)distributed uniformly throughout its volumec)clustered on its centerd)distributed uniformly over its surface

Matter is needed to transfer thermal energy bya. conductionb. convectionc. radiation d. both a & b.