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Two blocks of masses ml and m2, are placed on a table in contact with each other as discussed in Example 5.7 and shown in Figure 5.13a. The coefficient of kinetic friction between the block of mass m1 and the table is pi., and that between the block of mass m2 and the table is g2. A horizontal force of magnitude Pis applied to the block of mass mi. We wish to find P, the magnitude of the contact force between the blocks. (a) Draw diagrams showing the forces for each block. (b) What is the net force on the system of two blocks? (c) What is the net force acting on mi? (d) What is the net force acting on m2? (e) Write Newton's second law in the x direction for each block. (f) Solve the two equations in two unknowns for the acceleration a of the blocks in terms of the masses, the applied force F, the coefficients of friction, and g. (g) Find the magnitude P of the contact force between the blocks in terms of the same quantities.
Two blocks with masses of 46.4 kg and 24.9 kg are stacked on a table with the heavier block on top. The coefficient of static friction is 0.630 between the two blocks and 0.290 between the bottom block and the table. A horizontal force is slowly applied to the top block until one of the blocks moves. The acceleration of gravity is 9.81 m/s2.
a) What is the friction force between the blocks? Answer in units of N.
b) What is the friction force between the lower block and the table? Answer in units of N.
c) What minimum value for the coefficient of static friction between the masses and the table would cause the slippage to first happen between the blocks?
