Is My Kinematics Problem-Solving Approach Correct?

[chrisfnet]

I was wondering, given my solutions and the problem statements; if someone could look over my work to see if there are any incorrect solutions/processes.

Thanks!

 

[chrisfnet]

Problem 1

A ball is fired from a height of 3.0m above the ground, with a speed of 13m/s and an angle of 22 below horizontal. At what time does the ball hit the ground? What is the impact velocity?

Problem 2

A 28kg sign is suspended by two massless cables. Find the tension in each.

Problem 4

In the setup shown, m1 = 0.30kg, m2 = 0.45kg and theta = 11. Also, between the first block and incline, mu = 0.40. Assume the system moves so that the first block slides up the incline. What is the acceleration of the system? What is the tension in the string?