Terminal velocity -parachutist.

Terminal velocity

Free Fall is when an object is falling with no driving force (other than Gravity) acting on it. A free-falling objeact in a Fluid (e.g. air) will eventually reach Terminal Velocity. The most commn example is a sky diver.FREE FALL 1+initially only weight acts. The skydiver accelerates.+After a while he speeds up and drag force increases as he gets faster. The resultant force reduces, so his rate of acceleration reduces, still speeding up but not as much as before.+Drag increases until it is the same size as the weight - it can't increase after that .+At this point the resultant force is zero, so no more acceleration occurs. As he can't get faster the drag can't increase. This is called Terminal VelocityFREE FALL 2 + When the parachutist opens his parachute, when he does there would be a very large upwards force because of the large surface area and fast speed=large drag force+The large drag force creates a large resultant force. The resultant force is now upwards, so the parachutist decelerates. As he slows down the drag force decreases. When it is the same sze as his weight, he no longer decelerates and has reached a slower terminal velocity.Weight = Mass (kg)X Gravity (N/kg)

Isaac Newton worked out the three laws of motion. First Law- Balanced Forces mean No change in velocity So long as the forces on an object are all balanced, then it'll just stay still, or else if it's alread moving it'll just carry on at the same velocity- so long as the forces are all balanced.1) When a train or car or bus or anything else is moving at a constant velocity then the forces on it must all be balanced.2) Things do NOT need a constant overall force to keep them moving.3) To keep going at a steady speed, there must be zero resultant force - and don't you forget it.Second Law- A resultant Force means Acceleration.If there is an unbalanced force, then the object will accelerate in that direction.1) An unbalance force will always produce acceleration (or deceleration). 2)This "acceleration" can take 5 different forms: starting, stopping,speeding up,slowing down and changing direction.3)On on a force diagram, the arrows will be unequal.  

The Three laws of Motion

Dont ever say:" if something's moving there must be an overall resultant force acting on it"?. Not so if there is an overall force it.You get steady speed from balanced forces. Three points which should be obvious:1) The bigger the frce, the greater the acceleration or deceleration.2)The bigger the mass, the smaller the acceleration.3)To get a big mass to accelerate as fast as a small mass it needs a bigger force. The overall Unbalanced Force is often called the resistance

Terminal Velocity

The Three laws of motion

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