Phy Rev #2: About Forces Part 1

To start understanding forces, we must start by realizing what forces can do (Effects of Force)

A force applied on an object can:
1) Accelerate or decelerate an object (Stop to Move or Move to Stop)
2) Change the direction of a moving object (Includes circular motion)
3) Change the shape of an object (Stretch, press or pull)

What do you use force for?

Types of Forces:

Contact Forces	Non-Contact Forces
Frictional Force	Gravitational Force
Tension Force	Electrical Force
Normal Force	Magnetic Force
Air Resistance Force
Applied Force
Spring Force

Lets look at Tension/Spring Force for Now:

Introducing: Hooke's Law

Refer to this: 
http://www.schooltutoring.com/help/understanding-hookes-law/

Watch the Video:
http://www.youtube.com/watch?v=ZzwuHS9ldbY

Work it out:
 Hooke's Law Exercise:

1.If a spring has a spring constant of 2 N/m and it is stretched 5 cm, what is the force of the spring?            

2.  If a spring has a spring constant of 0.5 N/m and it is stretched 0.5 m, what is the force of the spring?

           

3.  A spring is stretched 6 cm when a mass of 200 g is hung on it.  Calculate the spring constant of this spring. 

4.If you use the spring from problem #3 and hang a 500 g mass on it, how far will it stretch?   Convert your answer to cm. 

5. A spring with a spring constant of 400 N/m has a mass hung on it so that it stretches 8 cm.  Calculate how much mass the spring is supporting. 

  

Answers:

1. (Answer = 0.1 N)          
2. (Answer = 0.25 N)
3. (Answer = 32.67 N/m)
4. (Answer = 15 cm)
5. (Answer = 3.3 kg)

MORE WORKOUT:
http://www.subneutrino.com/Physics%2011/5%20Dynamics/Physics%2011%20-%20Hookes%20Law.pdf