A thumb tack has an area of 0.5mm2 in contact with a wall.
A pressure of 40N/mm2
is needed for the drawing pin to go into
the wall.
Calculate the force needed to push the drawing pin into the wall.
Show your working and give the unit with your answer.

Rank the torques on the five doors shown in the figure above from least to greatest. note that the magnitude of all the forces is the same

Two manned satellites approaching one another at a relative speed of 0.550 m/s intend to dock. the first has a mass of 2.50 ✕ 103 kg, and the second a mass of 7.50 ✕ 103 kg. assume that the positive direction is directed from the second satellite towards the first satellite. (a) calculate the final velocity after docking, in the frame of reference in which the first satellite was originally at rest.(b) what is the loss of kinetic energy in this inelastic collision? (c) repeat both parts, in the frame of reference in which the second satellite was originally at rest. final velocity(d) loss of kinetic energy = ?

Consider an ideal gas at 27.0 degrees celsius and 1.00 atmosphere pressure. imagine the molecules to be uniformly spaced, with each molecule at the center of a small cube. what is the length l of an edge of each small cube if adjacent cubes touch but don't overlap?