RECF Mechanical Pre-Test.
15 mph - ANSsuppose an automobile travels 5 miles in 20 minutes. what is the
average speed of the car in miles per hour?
163 cubic inches - ANSwhat is the displacement of a 6 cylinder engine with a bore of
3.1 inches in diameter and a stroke of 3.6 inches? chose the nearest answer.
2.4 ft - ANStwo children are playing on a see-saw. the one on the left weighs 80 lbs
and the one on the right weighs 100 lbs. if the child on the left is 3 feet from the pivot,
how far must the child from the right be for the see-saw to be balanced?
284 N - ANSwhat is the minimum weight (W1) to hold the block (m2) static on the
ramp, if the ramp is inclined 30 degrees and the coefficient of friction between the
block and the ramp is 0.25? assume the pulley is frictionless.
3.0 - ANSwhat is the mechanical advantage of this lever if a = 1 inch and b = 3
inches?
31.4 in/s - ANSif a robot had 5 inch wheels that were spinning at 120 RPM, how fast
would the robot be moving?
4 - ANSwhat is the mechanical advantage of the nutcracker in the figure, where a = 2
inches and b = 8 inches?
5 ft/s^2 - ANSa robot starts from rest and accelerates to a speed of 20 ft/s in 4
seconds. what was the acceleration of the robot?
6:1 - ANSa motor is connected to a 12 tooth driver gear which meshes with a 72
tooth gear. the 24 tooth gear is paired with another 12 tooth gear on the same axle,
which is in turn meshed with a 36 tooth gear on the output shaft. what is the gear
ratio of the compound gear train?
60 lbs - ANSa torque of 30 ft*lbs is the result when a force of ________ acts on a 6
in. long wrench?
62.8 inches - ANSa robot has wheels with 4 inch diameter. Each wheel rolls 5
revolutions on a horizontal surface without slipping. how far did the robot travel?
acceleration would decrease by a factor of 2 - ANSaccording to Newton's second
law, if the mass of a moving object is doubled, what effect does it have on the
acceleration of the object?
clockwise - ANSa 12 tooth sprocket and a 36 tooth sprocket are connected by a
chain. if the 12 tooth sprocket is rotating clockwise, in whag direction is the 36 tooth
sprocket turning?
compressed gas - ANSpneumatics use _______ to produce mechanical motion.
counterclockwise - ANSin order to raise the arm of a roboy, the last of 4 spur gears
in a simple gear train must rotate clockwise. in what direction does the input (first)
gear turn?
energy cannot be created or destroyed - ANSwhich of the following statements is
equivalent of the first law of thermodynamics?
entropy - ANSwhich of the following is measured in the second law of
thermodynamics?
