1.) A 204 kg log is pulled up a ramp by means of a rope that is parallel to the surface of the ramp. The ramp is inclined at 30.0° with respect to the horizontal. The coefficient of kinetic friction between the log and the ramp is 0.820, and the log has an acceleration of 0.800 m/s2. Find the tension in the rope.
2.) The helicopter in the drawing is moving horizontally to the right at a constant velocity. The weight of the helicopter is W = 58300 N. The lift force generated by the rotating blade makes an angle of 21.0° with respect to the vertical.
(a) What is the magnitude of the lift force?
(b) Determine the magnitude of the air resistance that opposes the motion.
3.) A person pulls a toboggan for a distance of 30.0 m along the snow with a rope directed 20.0° above the snow. The tension in the rope is 86.0 N.
(a) How much work is done on the toboggan by the tension force?
(b) How much work is done if the same tension is directed parallel to the snow?
4.) A 5.70 x 102 kg hot-air balloon takes off from rest at the surface of the earth. The nonconservative wind and lift forces take the balloon up, doing +9.70 x 104 J of work on the balloon in the process. At what height above the surface of the earth does the balloon have a speed of 8.80 m/s?