HELP! Physics problems. vey important. very desperate.

We won't do your homework for you. Show us your work and we can give you a push in the right direction.

not asking for answers
hey man sorry if you got the wrong idea. all im asking for is some suggestions for each problem, because im basically clueless and these problems are very important. im not entirely sure how to go about answering them. i know the first problem has to do with the laws of right triangles and angular motion, im just not sure how to make the connection. how can i figure out how fast the ball is going? if anyone could just tell me what topics to research in order to understand these problems, it would be a great help. Thanks.

Equations for Velocity and Displacement Under Constant Acceleration

#1 seems more difficult than the others - I suspect that you are not supposed to worry about the angular momentum of the ball, but rather treat it as an object moving (accelerating) along a frictionless plane.

#2: You need to change the 10 m/s @ 10 degrees velocity into into horizontal and vertical components.
a) Once you have the vertical component, calculate the time gravity takes to reduce the speed to zero. Use the acceleration and time to calculate distance traveled.
b) Double the time you got in part a).
c) Take the time from b) and the horizonal velocity component and calculate distance traveled.

#4:
a) I'm assuming that there is no horizontal acceleration, so gravity is the only force acting on the ball
b) Vertical acceleration (gravity) and distance traveled will give you the vertical component of the speed. Use that with the total speed to calculate the horizontal component. Since there is no horizontal acceleration, that will give you the initial speed.
c) You already have the vertical and horizontal components of the speed. Use these to calculate the angle of the force.
d) Run your calculations over again with the new speed.

#1 you need to find out the component of gravity thats bringing it down, but then you would still need the mass to determine the acceleration, which is why "I suspect that you are not supposed to worry about the angular momentum of the ball, but rather treat it as an object moving (accelerating) along a frictionless plane.", as merlins said

#2 Vertical component = Vnet sinA, where A is the angle......so its 10sin20....so you have the initial V, and final V (0)..... acceleration = delta V / time......so a/(0-10sin20 m/s)=t.....then as merlins said, double it

part b, distance horizontal = Vnet²sin2A/g i believe....or else you can just figure it out the other way by using the horizontal component, with the newfound time, so d=Vaverage x t (v average will just be the horizontal component, because its constant)

#3 you need to know the river velocity direction...plus the question is kinda sketchy/hard to understand with your "directions" for the boat

#4 merlins answer is good.

so basically, for these questions, split the net velocity up into its components.....then if it asks for HORIZONTAL velocity, use the HORIZONTAL component, etc.

also, when finding time, its always easiest to use the vertical component, because you always have accel. (-9.8m/s²), Vf will always be 0 for the top of a parabola, and Vi can be gotten from Vnet.