(a) When rebuilding her car's engine, a physics major must exert 550 N of force to insert a oiled steel piston into a steel cylinder at a constant velocity. (Assume the coefficient of kinetic friction is 0.03.) What is the normal force between the piston and cylinder?
N
(b) What force would she have to exert if the steel parts are dry, so that the coefficient of friction is 0.3?
N
+33665 The resistive force is given by μ, where μ is coefficient of friction and M is normal force. For constant velocity there must be no net force acting on the piston, so μ*M = applied force
(a) 0.03*M = 550. M = 550/0.03 $${\mathtt{M}} = {\frac{{\mathtt{550}}}{{\mathtt{0.03}}}} \Rightarrow {\mathtt{M}} = {\mathtt{18\,333.333\: \!333\: \!333\: \!333\: \!333\: \!3}}$$ or M ≈ 18333N
(b) I'll leave you to do this.
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+33665 The resistive force is given by μ, where μ is coefficient of friction and M is normal force. For constant velocity there must be no net force acting on the piston, so μ*M = applied force
(a) 0.03*M = 550. M = 550/0.03 $${\mathtt{M}} = {\frac{{\mathtt{550}}}{{\mathtt{0.03}}}} \Rightarrow {\mathtt{M}} = {\mathtt{18\,333.333\: \!333\: \!333\: \!333\: \!333\: \!3}}$$ or M ≈ 18333N
(b) I'll leave you to do this.
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