Technician "A" states that in a disc brake system the brake caliper clamps the two brake pads against the brake rotor to slow the vehicle. Techician "B" states that in a
drum brake system the wheel cylinder pushes out against the two brake shoes that in
turn press against the inside of the brake drums to slow the vehicle. Who is correct?
-Tech A only
-Neither tech is correct.
-Both techs are correct
-Tech B only

Explain the difference laminar and turbulent flow. explain it with the shear stress and the velocity profiles.

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Aquick transition of the operating speed of a shaft from its critical speed will whirl amplitude. (a) increase (b) limit (c) not affect (d) zero