University physics 1 please show all work

15). The large block of mass M in the gure at right is sliding on _> _> a frictionless horizontal surface under the inuence of an applied horizontal force I? . Interface between the two blocks is rough and the acceleration of the system is large enough to prevent the I" 72 small block from sliding down the face of the larger block. How many forces are acting on the large block? A). 6 B). 4 C). 7 D). 5 16). A stunt motorcyclist starts from rest and accelerates up a straight ramp which makes an angle 6 = 150 with the horizontal. The mass of the motorcycle/rider is m = 250 kg and the coefcients of static & kinetic friction are ,u5 = 0.55 and ,uK = 0.45, respectively. Magnitude of the maximum acceleration the rider can achieve on the ramp is: A). 2.7 m/32 B). 2.2 m/32 C). 3.1 m/s2 D). 1.8 m/s2