Terminal Velocity Examples 57121g

Terminal Velocity Examples GCSE P2 When someone jumps out of a plane... 1. They start to accelerate towards the ground because of their weight force. This means that they gain speed; they get faster. 2. Air resistance (the drag force) increases with speed: the faster something is going, the more air resistance it has. The same is true of any friction. Therefore, the faster the skydiver is going, the more air resistance he has. 3. This continues until the air resistance is so large that it balances the weight force. The net force on the skydiver is zero, which means that he is no longer accelerating. 4. He has therefore reached his terminal velocity, and will continue at this speed until he opens his parachute.

For each of the following situations, fill in the missing step(s) that explains how it reaches terminal velocity. Some of the first letters have been filled in for you. 1) A steel ball sinks in a tube of oil. First, the steel ball experiences a downwards force, which is its This means it accelerates, gaining speed. As it gets faster, its

w. . . . . . . . . . . . . . . . . . . . . .

a. . . . . . . . . . . . . . . . . . . . . . . . .

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . also increases. This will increase until it balances the

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weight of the steel ball. When this happens, the net force on the ball is . . . . . . . . . . . . . . . .

t

Therefore, the ball has reached . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ., as it no longer accelerates.

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2) Someone leaves the handbrake off, and their car rolls down a hill.

a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . down the hill. However, weight is not the only f. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . acting on the car. There is also f. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ., which increases when the car gets f. . . . . . . . . . . . . . . . . . . . . . . . . This increases up to the point when . . . . . . . . . . . . . . . . . . . . . Because of the weight of the car, it

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . When this happens, the car is travelling at its terminal velocity. http://phy.si

a

Terminal Velocity Examples GCSE P2 3) A bubble rises to the surface of a swimming pool.

u. . . . . . . . . . . . . . . . . . . , which is a force that pushes something upwards, because it is less dense than water. It also experiences w. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i, which is a type of friction. As the bubble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i, this friction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iuntili. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iWhen this happens, the bubble . . . . . . . . . . . . . . . . . . . . . . . ................................................. i

The bubble experiences an

This question is not about terminal velocity, but the surprising ability of friction. A bullet is fired Arnie, who is swimming just below the surface of the water, fleeing his enemies.

i

This time there is no force present at first, but the bullet has a very large velocity. The air resistance is very small, but when it enters the water it experiences

w. . . . . . . . . . . . . . . . . .

wThis reduces the bullet’sw. . . . . . . . . . . . . . . . . . . . . . . until it . . . . . . . . . . . . . . . . . . . . . . . . . . . .wTherefore, Arnie is able to swim away unharmed. ..............................

Now write a step-by-step explanation of how a lead weight dropped to the bottom of the sea will reach terminal velocity.

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