21. suppose that a particular machine in a factory has two steel pieces that must rub against
each other at a constant speed. before either piece of steel has been treated to reduce
triction, the force necessary to get them to perform properly is 5.8 n. after the pieces
have been treated with oil, what will be the required force?

Apackage of supplies is dropped from a plane, and one second later a second package is dropped. neglecting air resistance, the relative velocity of the 1st package viewed from the second will 56) a) increase. b) be constant. c) be zero. d) depend upon their weight. e) decrease

Atriangle with equal sides of length 10 cm has -2.5-nc charged objects at each corner. part a determine the direction of the electrical force exerted on the object at the top corner due to the two objects at the horizontal base of the triangle. determine the direction of the electrical force exerted on the object at the top corner due to the two objects at the horizontal base of the triangle. horizontally rightward vertically downward vertically upward horizontally leftward

Ajoint produces movement when its angle decreases. which type of movement is it?