Problem 1:
Two blocks are connected over a pulley as shown in figure below. The mass of block A is 5 kg and the mass of block B is 1.5 kg. The block A is moving down the q = 38o- incline with constant speed.
a) Draw a free-body diagram for the block A and the block B.
b) Find the coefficient of kinetic friction m k between block A and the incline .
EXTRA CREDIT QUESTION (5 POINTS)
c) If the 1.5-kg block B is replaced by a block of mass 2 kg, will the system move in the same direction , will it stop or will it move in the opposite direction ? Explain showing your work. (coefficient of static friction m s = 0 .55)
Problem 2:
A 0.6-kg block with initial velocity v1 = 4.2 m/s ascends a frictionless ramp to the higher level where its velocity decreases to v2 = 2.4 m/s. The block reaches point A and moves onto a rough section whose coefficient of kinetic friction is 0.25. Due to the friction the velocity of the block decreases and at point B is v3 = 1.2 m/s.
a) What is the height h between the upper and lower levels of frictionless ramp?
b) Find the work done by friction, between point A and B in SI units.
c) What is the distance x that the block travels from point A to point B?
d) If at point B the block is brought to stop by a spring , compressing the spring a distance 5 mm from its initial position, what is a spring constant of this spring?
