Jhevon Needs Help With Physics

My cousin asked me to help her with some of her physics homework questions. It's been ages since i've done physics and even then, the type of questions i did were different from these. i'm currently trying to find ways to attack these problems, but any additional help will be much appreciated.

Please be advised that i posted these questions on 2 other forums. so check if a question you are planning to answer has been answered there

Art of Problem Solving Forum

Help With Physics Homework

Here are the questions:

4.9)

A 0.140 kilogram baseball traveling 35.0 m/s strikes the catcher's mitt, which, in bringing the ball to rest, recoils backward 0.11 meters. What was the average force applied by the ball on the glove?

4.25)

One 3.20 kilogram bucket is hanging by a massless cord from another 3.20-kilogram bucket, also hanging by a massless cord. (a) is the buckets are at rest, what is the tension in each cord? (b) If the two buckets are pulled upward with an acceleration of 1.60 meters per second squared by the upper cord, calculate the tension in each cord.

4.54)

A roller coaster reaches the top of the steepest hill with a speed of 6.00 kilometers per hour (1.67 meters per second). It then descends the hill, which is at an average angle of 45.0 degrees and is 45.0 meters long. What is its speed when it reaches the bottom? Assume the kinetic coefficient of friction is 0.18.

5.15)

How many revolutions per minute would a 15-meter-diameter Ferris wheel need to make for its passengers to feel "weightless" at the topmost point?

5.37)

A typical white dwarf star, which was once an average star like our sun but is now in the last stage of its evolution, is the size of our moon but has the mass of our sun. What is the surface gravity on this star?

5.48)

During an Apollo lunar landing mission, the common module continued to orbit the moon at an altitude of about 100 kilometers. How long did it take to go around the moon once?

for the first question i tried using the suvat equation $\displaystyle v^2 = u^2 + 2as$ to find the acceleration and then finishing off with F = ma to find the force. but the answer seems weird to me, is this the right way?

for the rest of the questions, i have no clue (at the moment at least)