Blocks A, B, and C are connected using rope of negligible mass (see figure below). Both A and B weight 23.8 N each, and the coefficient of kinetic friction between each block and the surface is 0.32. Block C descends with constant velocity.
a) Draw free body diagram for blocks A and B.
b) Find tension in rope connecting blocks A and B.
c) What is the weight of block C?
d) If the rope connecting A and B were cut, what would be the acceleration of block C?
Analyze the problem:
The problem has three blocks attached by an inelastic string (so they should have the same acceleration) and pulleys mass ignored. The surface where Blocks A and B are set on have friction and the kinetic friction coefficient was given (kinetic friction coefficient is involved when bodies are in motion which is different than static friction coefficient which used when bodies are not in motion).
What are the given information?
- Block A weight, FwA=23.8 N
- Block B weight, FwB=23.8 N
- Kinetic friction coefficient for all surfaces = 0.32
- Block C velocity is constant, so acceleration, a =0 m/s2
What are the needed information?
- Body-diagram draw for blocks A and B.
- Tension in rope attaching block A and block B.
- The weight of Block C
- When rope between block A and block B were cut , then find the acceleration of block C.
Note: The acceleration shown in figure below is for part (d).