1- The girl at C stands near the edge of the pier and pulls in the rope horizontally at a
constant speed of 6 ft/s. Determine how fast the boat approaches the pier at the instant the
rope length AB is 50 ft.
2- The jet plane is traveling at a constant speed of 1000 ft/s along the curve y = 20(10−6)x2
+ 5000, where x and y are in feet. If the pilot has a weight of 180 lb, determine the normal
and tangential components of the force the seat exerts on the pilot when y = 10 000 ft.
3- The 50-lb load is hoisted by the pulley system and motor M. If the motor exerts a
constant force of 30 lb on the cable, determine the power that must be supplied to the
motor if the load has been hoisted s = 10 ft starting from rest. The motor has an efficiency
of ε = 0.76.
4- The 5-lb collar is released from rest at A and travels along the smooth guide.
Determine its speed when its center reaches point C and the normal force it exerts on the
rod at this point. The spring has an unstretched length of 12 in., and point C is located
just before the end of the curved portion of the rod.
5- Two smooth disks A and B each have a mass of 0.5 kg. If both disks are moving with
the velocities shown when they collide, determine the coefficient of restitution between
the disks if after collision B travels along a line, 30° counterclockwise from the y axis.
6- The 10-lb block is originally at rest on the smooth surface. It is acted upon by a radial
force of 2 lb and a horizontal force of 7 lb, always directed at 30° from the tangent to the
path as shown. Determine the time required to break the cord, which requires a tension T
= 30 lb. What is the speed of the block when this occurs? Neglect the size of the block
for the calculation.
7- Determine the angular velocity of link AB at the instant shown if block C is moving
upward at 12 in./s.