1. how does the friction affect forward
motion? give an example.
2. describe two ways to change the
frictional force between two solids surfaces.
change the lubrication between the two surfaces
change the normal force between the two surfaces
3. how does air resistance affect the
velocity of a falling object?
4. what two sources of friction do you
have to overcome when you are walking?
5. if you push a chair across the floor
at a constant velocity, how does the force of friction compare with the force
exert? explain.
6. if you push a book against a wall
hard enough, it will not slide down even though gravity is pulling it. use what
you know about newton’s laws of motion to explain why the book doesn’t fall.

1.       Friction affects forward motion by repelling or trying to cancel the force which the opposite of its direction. For example, the wheel against the road pavement.

3. Air resistance affect the velocity of a falling object by either interfering with the gravitation force the object is acting on the subject. Hence, these since air assuming that the direction is perpendicular with gravity will result the object to drop sideways or gradually.  

4. The friction of the pavement and the air molecules.

5. Since the exerted force of the human is greater the object moves until the frictional force cancel itself or produce a net force both the force of the chair, gravity and friction.

6. Third law of motion which states that the force exerted of A to B, B will exert the same force that was exerted by A leaving the gravitational force canceled.