Physics problems are not hard to solve if you stick to a problem solving strategy.  This is how you do it when you want to think about Newton's Laws....

SOLVING PROBLEMS
1) Draw a picture of what is happening.  It will help you think about what's happening to the object and what it will do.
2) Draw a simple picture of the object all by itself (it's a free body now!).
3) Use a coordinate system to indicate what is up and what is down, what is right and what is left.
4) Draw in the forces using arrows to show which direction the force points.  Now you have a Free Body Diagram.
5) Now look at your  Free Body Diagram. To find the acceleration of the object you need to apply Newton's Second Law, F=ma. The forces you drew up and down sum
    to give you your mass times acceleration in vertical direction.  The Forces you drew  to the right and left sum to give you the mass times acceleration in the horizontal direction.
 

Get out some paper and lets try  a problem together!

Question 1: You drop a ball off the roof of your school. How fast is it accelerating towards the ground?
1) Picture 1: Draw the picture of the ball falling off the roof.
2) Picture 2: Draw a picture of the ball by itself.
3) What's up, down, left, right?  Question 2: What is a cartesian coordinate system? How would you use it in this problem?
4) Now draw in the forces. The ball is just falling, you didn't throw it so the only force acting on the ball is gravity. (Lets pretend there isn't any wind today.)  As you may have learned in the previous section, near the earths surface gravity causes a constant acceleration of 9.8 m/s. This acceleration is represented by the letter g. The force of gravity is determined by the mass of the object times the acceleration due to gravity so for short we write this as mg.

Question 3: Does mg give you the right units?
The units for force are Newton's which are kilograms*meters/seconds/seconds (kg*m/s² ).  The force of gravity on an object is often referred to as an objects weight.
Question 4: What is the difference between weight and mass?
Question 5: Why would your weight be different on the moon?

5) Look at your Free Body Diagram and add up the forces in the x direction then add up the forces in the y direction.

There are no forces acting in the x direction, so F=ma=0 and it doesn't accelerate in the x direction.
We have one force in the y direction. Our force is mg, so F=-mg=ma, so our acceleration, a =-g which means we are accelerating at 9.8m/s²   .
 

Did your Picture Look Like Mine?
 

Now try this one!
Question 6: A book is sitting on a desk, draw its free body diagram. What is its acceleration? Make sure you follow the problem solving strategy!
Don't' Forger your Free Body Diagram, Picture 3.

Explanation:
The book is not moving and its not going to so it definitely  has an acceleration of 0. Things that are not accelerating still have a Free Body Diagram, since acceleration is zero we know that forces can still be acting on the object but they balance each other. So lets look at the book.  Gravity is pulling down. How did I represent that in  my FBD?  The table is pushing up on the book. I have represented this by an N because forces due to contact with another object are called Normal Forces.
 
 

Now for the Newton's Second Law F=N-mg=ma=0 because the book isn't accelerating. Its just hanging out.
 

By Newton's third Law for every force there is an equal force in the other direction.
Question 7: Where is the force in the other direction for N? (Hint its not mg)  Now draw the Free Body Diagram for the Table, Picture 4.  If you want a challenge draw the free body diagram for the earth too, Picture 5.

Try this one on your own:
Question 8: Your yo-yo unwinds and is just sitting there at the bottom of the string how much force must you exert to keep it from falling to the ground? The yo-yo is one of the old fashioned wooden kinds and weighs 0.5kg.
Don't Forget your Free Body Diagram, Picture 6!
 

If you completed this worksheet you should have answered 8 questions and should have at least 6 pictures on your paper!