Force diagrams

1. Force diagrams

2. A force is • A push or pull • Measured in strength (magnitude) and direction • They can be added (or subtracted if in opposite directions) • The total force is the net force acting on an object • If the object is not moving or not changing its motion the forces are balanced and the net force is 0 • If the forces are unbalanced there is a change in motion.

3. Forces are measured in Newtons • We use a capital N to abbreviate Newton • Remember this is a measure of force • It is measured with a newton meter aka spring scale • 1 N = 1kg of mass at 1 meter/1 second² • Kg m/s²

4. Types of forces • Indirect: • Electric • Magnetic • Gravitational • Or via direct contact

5. What to use • Gravity = always points towards the center of the Earth • Normal Force = the opposite of gravity • Applied force= in direction the force is applied • Friction= opposes applied force • This is used to show if the forces are balanced or not. When forces are balanced an object will not move and no work is done.

6. Examples A 240 lb cow is standing in a field, draw the force diagram. The cow is not moving. 240 lb NF 240 lb GF

7. You try. You push a cup with 2N of force. The cup moves with 1N of force.