When stopping a car on an icy or wet road … or a dry road, for that matter … is it better to push the brake pedal hard enough to lock the wheels and make them slide or to push gently so that the wheels continue to roll? What is the point behind "anti-lock disk brakes"?
Young and Freedman 5-79
: Consider the drawing below (or Figure 5-58 on page 158 of the text). In terms of m1, m2 and g, find the accelerations of each block in the system. Assume there is no friction anywhere in the system.
Now, for the system considered in the question above, assume there is friction between m1 and the table surface. What is the minimum value of m s that will keep the blocks from moving? Why do I ask for m s and not m k?
Young and Freedman 6-6:
A bucket of mass 7.25 kg hangs in a well at the end of a rope. The rope passes over a frictionless pulley at the top of the well, and you pull horizontally on the end of the rope to raise the bucket slowly a distance of 6.00 m. a) How much work do you do on the bucket in pulling it up? b) How much work is done by the gravitational force acting on the bucket? C) What is the total work done on the bucket?
In the above question, why does it specify that you raise the bucket slowly? Suppose you raised it quickly with varying acceleration? How would this change the problem?
You move a big box up a frictionless inclined plane. Does the inclined plane save you work? If not, what is the advantage of using an inclined plane for lifting the box?
A 30 g bullet initially traveling 500 m/s penetrates 12 cm into a wooden block. What average force does it exert on the block?
if time permits -
Use work-energy considerations to solve Young and Freedman 6-12: A car is stopped by a constant friction force that is independent of the car's speed. By what factor is the stopping distance changed if the car's initial speed is doubled?