A

A sled of mass 500kg sits at rest on a rough slope that is inclined at 10* to the horizontal. The coefficient of friction between the slope and the sled is 0.3. The sled is held in place by a wire attached to a winch. The tension in the wire is TN. a) Find the maximum possible value of T. A load of mass mkg is added to the sled, and tension in the wire is increased to 5000N in order to pull the sled and load up the slop. Given that the sled and load are pulled a distance of 100m in 80seconds, b) Work out the value of m

(a) A 4.53 kg salami is supported by a cord that runs to a spring scale, which is supported by another cord from the ceiling (see Figure (a)). What is the reading on the scale, which is marked in weight units? (b) In Figure (b) the salami is supported by a cord that runs around a pulley and to a scale. The opposite end of the scale is attached by a cord to a wall. What is the reading on the scale? (c) In Figure (c) the wall has been replaced with a second 4.53 kg salami on the left, and the assembly is stationary. What is the reading on the scale now? Spring scale Spring scale (6) Spring scale (a) (c) (a) Number i Units (b) Number i Units (c) Number i Units

A skydiver weighing 65 kg jumps out of a helicopter hovering at a height of 3 kilometers. Assume a cross-sectional area of 0.5 square meters. After thirty seconds of free fall, the skydiver deploys the parachute and the cross-sectional area becomes 40 square meters. Reproduce the model for the skydiver in Excel or VenSim. In VenSim you may have to make At quite small in order not to throw an error. Because you reach terminal velocity relatively quickly your answer should not be particularly sensitive to the value of At you choose. What is the skydiver's terminal velocity without the parachute? meters/second What is the skydiver's terminal velocity with the parachute? meters/second

3. The force F required to move a box by pulling on an attached rope that forms an angle w with the horizontal is given by fmg F(w) = cOSw + f sin w where f, m, g > 0 are all constant. (a) Show that the angle wo that minimizes the required force to set the box in motion is given by arctan(f) (b) Show that this minimal force F(wo) is proportional to (a constant multiple of)

A 22-kg crate is on an incline that makes an angle of 30° with the horizontal. If the coefficient of static friction is 0.50, the minimum force that can be applied parallel to the plane to hold the crate at rest is:

(a) A 2.25 kg salami is supported by a cord that runs to a spring scale, which is supported by another cord from the ceiling (see Figure (a)). What is the reading on the scale, which is marked in weight units? (b) In Figure (b) the salami is supported by a cord that runs around a pulley and to a scale. The opposite end of the scale is attached by a cord to a wall. What is the reading on the scale? (c) In Figure (c) the wall has been replaced with a second 2.25 kg salami on the left, and the assembly is stationary. What is the reading on the scale now? Spring scale Spring scale (b) Spring scale (a) (c) (a) Number Units (b) Number i Units (c) Number Units