12. A vacuum leak is detected in an automot engine. Technician A says the leak should
most noticeable at highway speeds. Technic
B says the vacuum leak should be most not
able at idle. Who is right?
(A) A only.
(B) B only.
(C) Both A and B.
(D) Neither A nor B.

A21-tooth spur pinion mates with a 28-tooth gear. the diametral pitch is 3 teeth/in and the pressure angle is 20°, find the following values: the addendum, dedendum, circular pitch, tooth thickness, and base circle diameters.

Asimple speed reducer is composed of 2 spur gears. the pinion gear has a pitch diameter of 0.75" and 36 teeth while the driven gear has a pitch diameter of 4.0" and 192 teeth. a)-what is the diametral pitch of each gear? b)-if an electric motor rotating ccw at 3000 rpm is coupled to the pinion, what is the rotational speed of the driven gear? c)-if the torque delivered to the pinion is 1 n-m, what is the torque on the driven gear? d)-what is the power transmitted by the gear train?

A75mm diameter shaft is supported in a journal bearing 75mm long with a diametral clearance of 0. 1mm. it supports a radial load of 1000 n and is lubricated with sae 50 oil at 70°c. find the friction torque and the power loss when the crankshaft rotates at 2900 rev/min.