Mechanics Practical Number 2
Centrifugal Force Apparatus HFC21
The object of the experiment is to verify that the centrifugal force varies in direct proportion to 1. The mass of the rotating body M (Experiment parts 1 and 2) 2. The square of the speed of rotation ω (Experiment part 3) 3. The radius of gyration k (Experiment part 4) In accordance with the formula; F = Mω2k
Centrifugal Force Apparatus HFC21, Cast iron calibrated weights arranged as in Figs.1 and 2.
Figure 1 Centrifugal Force Apparatus HFC21
Figure 2 Centrifugal Force HFC21 detail
According to Newton's first law of motion, a moving body travels along a straight path with constant speed (i.e., has constant velocity) unless it is acted on by an outside force. For circular motion to occur there must be a constant force acting on a body, pushing it toward the center of the circular path. This force is the centripetal (“center-seeking”) force. For a planet orbiting the sun, the force is gravitational; for an object twirled on a string, the force is mechanical; for an electron orbiting an atom, it is electrical. The magnitude F of the centripetal force is equal to the mass m of the body times its velocity squared v 2 divided by the radius r of its path: F=mv2/r. According to Newton's third law of motion, for every action there is an equal and opposite reaction. The centripetal force, the action, is balanced by a reaction force, the centrifugal (“center-fleeing”) force. The two forces are equal in magnitude and opposite in direction. The centrifugal force does not act on the body in motion; the only force acting on the body in motion is the centripetal force. The centrifugal force acts on the source of the centripetal force to displace it radially from the center of the path. Thus, in twirling a mass on a string, the centripetal force transmitted by the string pulls in on the mass to keep it in its circular path, while the centrifugal force transmitted by the string pulls outward on its point of attachment at the center of the path. The centrifugal force is often mistakenly thought to cause a body to fly out of its circular path when it is released; rather, it is the removal of the centripetal force that allows the body to travel in a straight line as required by Newton's first law. If there were in fact a force acting to force the body out of its circular path, its path when released would not be the straight tangential course that is always observed.
Centrifugal Force, in physics, the tendency of an object following a curved path to fly away from the center of curvature. Centrifugal force is not a true force; it is a form of inertia (the tendency of objects that are moving in a straight line to continue moving in a straight line). Centrifugal force is referred to as a force for convenience—because it balances centripetal force, which is a true force. If a ball is swung on the end of a string, the string exerts centripetal force on the ball and causes it to follow a curved path. The ball is said to exert centrifugal force on the string, tending to break the string and fly off on a tangent.
Record the individual weights of the CF weights into table 1. The weight of the CF shafts is nominally 0.03Kg (30grams). As these parts are not removable then this is the value of the CF shafts that should be used and recorded. Part 1 (Self weight and mass) No CF Weights added to CF shafts This part of the experiment does not require the CF weights to be added to the CF shaft. REMOVE ANY CF WEIGHTS THAT ARE MOUNTED ONTO THE SHAFT. To compensate for self-weight due to the CF shafts being rotated it is essential to establish the centrifugal forces readings without any CF weights added. In the first place turn the power onto the unit without the dome fitted. Ensure no CF weights are added to the shaft. Check the force display functions by pushing down the thrust plate at the centre of the...
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