a ladder at rest is leaning against a wall at an angle. which of the following forces must have the same magnitude as the frictional force exerted on the ladder by the floor? justify your answer. (a) the force of gravity on the ladder (b) the normal force exerted on the ladder by the floor (c) the frictional force exerted on the ladder by the wall d) the normal force exerted on the ladder by the wall

Four 5-gram blocks of metal are sitting out in the sun and absorb the same amount of heat energy. use the following specific heat capacity data to determine which block will increase its temperature the most.

Ahole in the ground in the shape of an inverted cone is 14 meters deep and has radius at the top of 11 meters. the cone is filled to the top with sawdust. the density of the sawdust depends upon the depth, x, following the formula ρ ( x ) = 2.5 + 1.2 e − 0.7 x kg/m3. find the total mass of sawdust in the conical hole.

Oxygen gas enters well-insulated diffuser at 25 lbf/in.2, 420r, with a velocity of 860 ft/s through a flow area of 1.6 in.^2. at the exit, the flow area is 12 times the inlet area, and the velocity is 19 ft/s. the potential energy change from inlet to exit is negligible. assuming ideal gas behavior for the oxygen and steady-state operation of the diffuser, determine the following: (a) the exit temperature, in r(b) the exit pressure, in lbf/in.^2 (c) the mass flow rate, in lb/s