The wall of a refrigerator is constructed of fiberglass insulation (k = 0.035 w/m·k) sandwiched between two layers of 1-mm-thick sheet metal (k = 15.1 w/m·k). the refrigerated space is maintained at 3°c, and the average heat transfer coefficients at the inner and outer surfaces of the wall are 4 w/m2·k and 9 w/m2·k, respectively. the kitchen temperature averages 25°c. it is observed that condensation occurs on the outer surfaces of the refrigerator when the temperature of the outer surface drops to 20°c. determine the minimum thickness of fiberglass insulation that needs to be used in the wall in order to avoid condensation on the outer surfaces.

Luke and carrie are driving down a straight section of the interstate at 70 mph in luke's new convertible. carrie is drinking a soda in the passenger seat. when she is done she tosses the bottle straight up in the air, just above the height of the car. what will happen to the bottle if air resistance is neglected? a. the bottle will land in carrie's lap. b. not enough information is given. c. the bottle will land on the interstate in front of the car. d. the bottle will land on the interstate behind the car.

Athin plate moves between two parallel, horizontal, stationary flat surfaces at a constant velocity of v = 7.5 m/s. the two stationary surfaces are spaced 4 cm apart, and the medium between them is filled with oil whose viscosity is 0.9 n·s/m2. the part of the plate immersed in oil at any given time is 2 m long and 0.5 m wide. if the plate moves through the mid-plane between the surfaces, determine the force required to maintain this motion. what would your response be if the plate was 1 cm from the bottom surface (h2) and 3 cm from the top surface (h1)? if the plate moves through the mid-plane between the surfaces, the force required to maintain the motion will be n. if the plate was 1 cm from the bottom surface (h2) and 3 cm from the top (h1) surface, the force required to maintain the motion would be n.

The system is released from rest with the cable taut, and the homogeneous cylinder does not slip on the rough incline. determine the angular acceleration of the cylinder and the minimum coeffi cient s of friction for which the cylinder will not slip.