3. Forces Physics Notes PDF

### 3. Forces - push - pull **Newton "N"** **Contact** 1. Friction 2. Air Resistance 3. Tension 4. Upthrust 5. Normal Force **At a distance** - Gravity - Electricity - Magnetism **Net Force** = mass x acceleration **Weight** = mass x gravity accel (9.8 m/s²) **Free Fall**: under effect of gra...

### 3. Forces - push - pull **Newton "N"** **Contact** 1. Friction 2. Air Resistance 3. Tension 4. Upthrust 5. Normal Force **At a distance** - Gravity - Electricity - Magnetism **Net Force** = mass x acceleration **Weight** = mass x gravity accel (9.8 m/s²) **Free Fall**: under effect of gravity - Ignore air Resistance - accel = g = 9.8 m/s² - Constant Speed **Skydiving**: | | No air R | 200N | 400N | 784N | 2000N Up | |---|---|---|---|---|---| | | 80kg | 80kg | 80kg | 80kg | | | W=mg=784N | 784N | 784N | 784N | 784N | | | Net F | 784N | 584N | 384N | Zero | 1216N | | a=F/m | 9.8 m/s² | 7.3 m/s² | 4.8 m/s² | Zero | 15.2 m/s² | **Air Resistance increases - Net F² decreases - accel decreases** **open Parachute decel.** **Weight = Air Resistance Net F² = zero accel ↓ Constant speed Terminal velocity** **Circular Motion = Curved path** **Force needed = Centripetal Force** - Direction Changes - Velocity Changes - Centripetal acceleration **Directed toward the Centre** **Diagram** A circle with an arrow pointing upwards at the top and a smaller arrow pointing left. Inside the circle, an F is marked pointing to the left. Then, the arrow starting at the top is pointing right and another arrow pointing left starts at the bottom of the circle. All the arrows inside the circle, both large and small, are pointing in the same direction as the arrows outside the circle. There is a 2mls at the top, bottom, left and right of this circle.