4: During a very quick stop, a car decelerates at 7.4 m/s2. Assume the forward motion of the car corresponds to a positive direction for the rotation of the tires (and that they do not slip on the pavement). A) What will be the angular acceleration of its tires in rad/s2, assuming they have a radius of 0.255 m and do not slip on the pavement? B) How many revolutions do the tires make before coming to rest, given their initial angular velocity is 95 rad/s ? Part (c) How long does the car take to stop completely in seconds? Part (d) What will be the distance does the car travel in this time in meters? Part (e) What will be the car's initial speed in m/s? Problem 5: Suppose you exert a force of 185 N tangential to the outer edge of a 1.71-m radius 76-kg grindstone (which is a solid disk). A) What will be the torque , in newton meters, you are exerting on the grindstone, relative to the center of mass of the grindstone? B) What will be the angular acceleration of the grindstone 0, in radians per square second, assuming negligible friction? C) What will be the angular acceleration of the grindstone f, in radians per square second, if there is an opposing frictional force of 19.5 N exerted 0.45 m from the axis? Problem 6: You have a horizontal grindstone (a disk) that is 86 kg, has a 0.36 m radius, is turning at 85 rpm (in the positive direction), and you press a steel axe against the edge with a force of 22 N in the radial direction. A) Assuming that the kinetic coefficient of friction between steel and stone is 0.20, calculate the angular acceleration of the grindstone in rad/s2. Part (b) What is the number of turns, N, that the stone will make before coming to rest