Question

1. Adjust the angle of inclination of the ramp to be larger than the critical angle you found in the previous experiment. Place the block at the top of the ramp, carpeted side down, and release it. a Describe the motion of the block. If the block does not remain at rest, does the speed of the block increase, decrease, or remain constant? Block on Inc line b. In the space provided at right, draw a free body diagram of the block for a moment after it is released. Label the forces in the same manner as you have done previously. c. The force of kinetic friction f between two objects is independent of the relative speeds of the objects. Furthermore, the coefficient of kinetic friction between two objects is defined as the ratio between the magnitudes of the force of kinetic friction and the normal force: N (Note: We will assume that the coefficient of kinetic friction between two objects is independent of the relative velocity or the relative acceleration of the objects.) Use the above information to answer the following questions: As the block moves down the ramp, does the net force on the block increase, decrease, or remain constant? Explain how you know. What can you then say about the acceleration of the block down the ramp? Is it zero? If not zero, is the acceleration constant, and in which direction is it? Explain your reasoning. Use your free-body diagram and Newton's 2nd law to express the coefficient of kinetic friction 4 in terms of the acceleration a of the block, the mass m of the block, g, and (Hint: Resolve force vectors into components parallel to and perpendicular to the incline.)

Answer 1

consider free body diagram a oft N. fret, mgsine for So To my fig. o force To ng coso Using Newton's law and from we can write free ma = mgsino-fk - where. fk = UK N . fictional and N= mg .. fx = lx mg. » ma=mgsino - limg a = g sino -eleg- © =) Ug = gsino-a lx = gsino-a _ g -

As block moves downward, Force e is constant and it is given by eq" 0 Also acceleration is constant given by egno @ As it is accelerated motion the I velocity will increase in direction 110 - to ramp and down words