A metal crossbar of mass M rides on a pair of long, horizontal conducting rails separated by
Question:
A metal crossbar of mass M rides on a pair of long, horizontal conducting rails separated by a distance ? and connected to a device that supplies constant current I to the circuit, as shown in Figure. A uniform magnetic field B is established as shown.
(a) If there is no friction and the bar starts from rest at t = 0, show that at time t the bar has velocity v = (BI ? /M)t.
(b) In which direction will the bar move?
(c) If the coefficient of static friction is ?s, find the minimum field B necessary to start the bar moving.
B in Constant current source
Step by Step Answer:
a b The force on the bar is F BI and its acceleration i...View the full answer
Fundamentals of Ethics for Scientists and Engineers
ISBN: 978-0195134889
1st Edition
Authors: Edmund G. Seebauer, Robert L. Barry
Related Video
Static friction and kinetic friction are two types of friction that occur when two objects are in contact with each other. Static friction is the force that must be overcome to initiate motion between two surfaces that are in contact with each other but are not moving relative to each other. It is caused by the interlocking of rough surfaces at the microscopic level, and it increases as the force pushing the surfaces together increases. Once motion between the surfaces starts, the static friction is no longer present. Kinetic friction, also known as sliding friction, is the force that opposes the motion of two surfaces that are in contact with each other and are moving relative to each other. It is caused by the rubbing of the surfaces against each other and the resistance of the molecules in the surfaces to being moved. Kinetic friction is generally less than static friction, but it can still be a significant force, especially at high speeds. Both static and kinetic friction can be quantified using a coefficient of friction, which is a dimensionless number that represents the ratio of the frictional force between two surfaces to the normal force (the force perpendicular to the surfaces). The coefficient of static friction is typically greater than the coefficient of kinetic friction for a given pair of surfaces, because it takes more force to overcome the interlocking of the surfaces at rest than to maintain motion once it has started.
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