MECE 2304 Dynamics Javier A. Kypuros, Ph.D.Summer 2008 Homework 6

Problem 1The pipe has a mass of 800 kg and is being towed behind a truck. If the angle =30o , determine the acceleration of the truck and the tensions in the cable. The coefficient of kinetic friction between the pipe and the ground is k=01 .

MECE 2304 Dynamics Javier A. Kypuros, Ph.D.Summer 2008 Homework 6

Problem 2The 20-kg roll of paper has a radius of gyration k A=90 mm about an axis passing through point A . It is pin-supported at both ends by two brackets AB . If the roll rests against a wall for which the coefficient of kinetic friction is k=0.2 and a vertical force F=30 N is applied to the end of the paper, determine the angular acceleration of the roll as the paper unrolls.

MECE 2304 Dynamics Javier A. Kypuros, Ph.D.Summer 2008 Homework 6

Problem 3The two blocks A and B have a mass mA and mB , respectively, where mBmA . If the pulley can be treated as a disk of mass M , determine the acceleration of block A . Neglect the mass of the cord and any slipping on the pulley. Recall that the moment of inertia of a disk about its center is I G=Mr

2/ 2 .

MECE 2304 Dynamics Javier A. Kypuros, Ph.D.Summer 2008 Homework 6

Problem 4The 20-kg punching bag has a radius of gyration about its center of mass G of kG=0.4 m. If it is initially at rest and is subjected to a horizontal force F=30 N, determine the initial angular acceleration of the bag and the

tensions in the supporting cable AB .

MECE 2304 Dynamics Javier A. Kypuros, Ph.D.Summer 2008 Homework 6

Problem 5The two pin-connected bars each have a weight of 10 lb/ft. If a moment of M=60 lb-ft is applied to bar AB , determine the initial vertical reaction at C and the horizontal and vertical components of the reaction at B . Neglect the size of the roller at C . The bars are initially at rest.