the terminal velocity of a falling body occurs during free fall when a falling body experiences zero...

8/3/2019 The Terminal Velocity of a Falling Body Occurs During Free Fall When a Falling Body Experiences Zero Acceleration A

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The terminal velocity of a falling body occurs during free fall when a falling body experiences zero

acceleration. This is because of the retarding force known as air resistance. Air resistance exists

because air molecules collide into a falling body creating an upward force opposite gravity. This upward

force will eventually balance the falling body's weight. It will continue to fall at constant velocity known as

the terminal velocity.

Terminal Velocity

After jumping from the aircraft the skydiver increasesspeed up to a steady maximum called terminal velocity.

The downward force of gravity (the Weight) is balanced by the upwardforce of air resistance (the Drag)


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A Hooke's Law Spring

Determine the Spring Constant


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Hooke's Law states that the restoring force of aspring is directly proportional to a smalldisplacement. In equation form, we write

F = -kx

where x is the size of the displacement. Theproportionality constant k is specific for eachspring.

The object of this virtual lab is to determine thespring constant k.

Displacement is measured in centimeters. Each ofthe blue weights has a mass of 50 grams. Thegray virtual weight hanger has no mass.

Snapshots of the lab are found in the four figuresthat follow.

50 grams mass is 2 cm displacement. 100 grams mass is 4 cm displacement.


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150 grams mass is 6 cm displacement. 200 grams mass is 8 cm displacement.

Mass(grams)

Displacement(cm)

50 2

100 4

150 6

200 8

These data have been entered into thetable to the left.

For each snapshot above the downwardpull of gravity is balanced by the upwardpull of the spring. A force or free-bodydiagram of this is shown on the right-hand side.

Note that the restoring spring force isgiven by Hooke's Law as kx.

Conservation of Energy with Examples

CONSERVATION OF ENERGY THEOREM

Nothing can be destroyed or created in the universe

like energy. Suppose that a ball falls from height of

2m, it has only potential energy at the beginning,


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however, as it falls it gains kinetic energy and its velocity increases. When it hits the

ground it has only kinetic energy. Well, where is the potential energy that it has at the

beginning? It is totally converted to the kinetic energy, as said in the first sentence

nothing can be destroyed or created they just change form. Thus, our potential energy

also changes its forms from potential to the kinetic energy. In summary, energy of the

system is always constant, they can change their forms but amount of total energy

does not change.

CONSERVATION

OF ENERGY

THEOREM


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Nothing can be destroyed or created in the universe

like energy. Suppose that a ball falls from height of

2m, it has only potential energy at the beginning,

however, as it falls it gains kinetic energy and its

velocity increases. When it hits the ground it has only

kinetic energy. Well, where is the potential energy that

it has at the beginning? It is totally converted to the

kinetic energy, as said in the first sentence nothing can

be destroyed or created they just change form. Thus,

our potential energy also changes its forms from

potential to the kinetic energy. In summary, energy of

the system is always constant, they can change their

forms but amount of total energy does not change.

CONSERVATION OF ENERGY THEOREM

Nothing can be destroyed or created in the universe like energy. Suppose that a ball

falls from height of 2m, it has only potential energy at the beginning, however, as it

falls it gains kinetic energy and its velocity increases. When it hits the ground it has

only kinetic energy. Well, where is the potential energy that it has at the beginning? It

is totally converted to the kinetic energy, as said in the first sentence nothing can be

destroyed or created they just change form. Thus, our potential energy also changes

its forms from potential to the kinetic energy. In summary, energy of the system is

always constant, they can change their forms but amount of total energy does not

change.


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We use

conservation of

energy in solution

of this problem.

Einitial=Efinal

Einitial=Ep+Ek=mgh+1/2mv Efinal=0

Einitial=2kg.10m/s.8m+1/2.2kg. (2m/s) Work done by friction=Einitial

Einitial=164joule

Wfriction=.N.X=0,4.2kg.10m/s.X=Ei

8. X=164joule X=20,5m

Block slides 20,5m in horizontal

Example: Find the final velocity of the box from the given picture.

We again use the conservation of energy theorem.

Einitial must be equal to the Efinal.

Einitial=Ek=1/2mv Efinal=Ek+Ep=1/2mv+mgh


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Ei=1/2.2kg.

(10m/s)

=100joule

Efinal=1/2.2kg.v+2kg.10m/s.4m=80+v

100=80+v v=25m/s

Example: Find the amount of compression of the spring if the ball does free fall from

4m and compresses the spring.

From the conservation of energy law we can find the amount of springs


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Potential Energy

Potential energy is stored energy and theenergy of position gravitational energy.

There are several forms of potentialenergy.

Kinetic Energy

Kinetic energy is motion of waves,molecules, objects, substances, and

objects.


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the terminal velocity of a falling body occurs during free fall when a falling body experiences zero...

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