Lou bets an innocent stranger that he can place a 8.0 kg block against the side of a cart, as in the figure below, and that the block will not fall to the ground, even though Lou will use no hooks, ropes, fasteners, magnets, glue, or adhesives of any kind. When the stranger accepts the bet, Lou begins to push the cart in the direction shown. The coefficient of static friction between the block and the cart is 0.50.
(a) Find the minimum acceleration for which Lou will win the bet.
______ m/s2
(b) What is the magnitude of the frictional force in this case?
______ N
(c) Find the force of friction on the block if a is twice the minimum needed for the block not to fall.
______ N
(d) Show that, for a block of any mass, the block will not fall if the acceleration is a ? g/?s, where ?s is the coefficient of static friction. (Do this on paper.)