4,5,6 and 7 please!!

4. A bullet of mass 100 grams is uniformly accelerated down an 80-cm rifle barrel, acquir ing a muzzle velocity of 80 m/s. a) What is its constant acceleration? b) What force (assumed constant) did the gunpowder impose on the bullet? 5 . A hand pushes two blocks across a frictionless pond of ice. Block A has mass ma = 1 kg and block B has mass MB = 4 kg. If the hand pushes with a constant horizontal force of 15 new- tons, find the magnitude of the normal force exerted by block B on block A. 6. A 5-kg mass is connected by a string to a 4-kg mass, and the string passes over a massless frictionless pulley so that the 5-kg mass sits on a tabletop and the 4-kg mass hangs straight down. If the system is static, what must be the frictional force acting between the tabletop and the 5-kg mass? 5 4 7. 100 N A block of mass M is held at rest by two strings, as shown in the picture at left. The 37% string pulling to the right has a tension of 100 N in it, as indicated. Find the tension in the other string and find the mass of the block. [Hint: In this problem, there are two unknowns, but you can solve for them one at a time. One equation will end up involving only one of the unknowns.]