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diamong [38]
3 years ago
5

The worlds fastest humans can reach speeds of about 11 m/s in order to increase his gravitational potential energy by an amount

equal to his Kinetic energy at full speed how high with the sprinter need to climb
Physics
1 answer:
Amanda [17]3 years ago
4 0
 
What a delightful little problem !

-- When he is running on level ground, his kinetic energy is

             KE = (1/2) x (mass) x (speed)² .

-- When he climbs up from the ground, his potential energy is

             PE = (mass) x (gravity) x (height above the ground).

We're looking for the height that makes these quantities of energy equal,
figuring that when he runs, his speed is  11 m/s.

The first time I looked at this, I thought we would need to know the runner's
mass.  But it turns out that we don't.

       <u>PE = KE</u>

      (mass) x (gravity) x (height) = (1/2) (mass) (11 m/s)²

Divide each side by (mass) : 

       (gravity) x (Height)  =  (1/2) (11 m/s)²

Divide each side by gravity:

                      Height = (1/2) (121 m²/s²) / (9.8 m/s²)

                                =  <em>6.173 meters</em>

                         (about  20.3 feet !)


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5 0
3 years ago
A particle is moving with (SHM) of period 8.0s and amplitude5.0m
nadezda [96]

Answer:

velocity(x)=15\,\frac{\pi}{4}\,cos(\frac{\pi}{4}x)

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Max acceleration = \frac{15\,\pi^2}{16} \,\,\frac{m}{s^2}

Explanation:

Given the description of period and amplitude, the SHM could be described by:

f(x)=5\,sin(\frac{\pi}{4}x)

and its angular velocity can be calculated doing the derivative:

f(x)=5\, \,sin(\frac{\pi}{4}x)\\f'(x)=5\,\frac{\pi}{4}\,cos(\frac{\pi}{4}x)

And therefore, the tangential velocity is calculated by multiplying this expression times the radius of the movement (3 m):

velocity(x)=15\,\frac{\pi}{4}\,cos(\frac{\pi}{4}x)  and is given in m/s.

Then the maximum speed is obtained when the cosine function becomes "1", and that gives:

Max speed = \frac{15\, \pi}{4} \,\, \frac{m}{s}

The acceleration is found from the derivative of the velocity expression, and therefore given by:

acceleraton(x)=-15\,\frac{\pi^2}{16}\,sin(\frac{\pi}{4}x)

and the maximum of the function will be obtained when the sine expression becomes "-1", which will render:

Max acceleration = \frac{15\,\pi^2}{16} \,\,\frac{m}{s^2}

6 0
3 years ago
A hockey puck is traveling to the left with a velocity of v=10 when it is struck by the hockey stick
Lera25 [3.4K]
We have to calculate the impulse of a hockey puck.
Imp = m * ( v 1 - v 2 ) = m * Δ v
v 1 = - 10 i m/s,
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Δ v = ( 15.32 i + 12.855 j ) - ( - 10 i ) =
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Imp = 0.2 kg * 28.4 m/s = 5.68 N-s
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4 0
3 years ago
A 1.50-V battery supplies 0.414 W of power to a small flashlight. If the battery moves 4.93 1020 electrons between its terminals
slamgirl [31]

Answer:

2.86×10⁻¹⁸ seconds

Explanation:

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P = VI................ Equation 1

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make I the subject of the equation

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From the question,

Given: P = 0.414 W, V = 1.50 V

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I = 0.414/1.50

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Also,

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From the question,

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5 0
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*PHYSICS HELP*
sveta [45]
My calculator is about 1cm thick, 7cm wide, and 13cm long.

Its volume is (length) (width) (thick) = (13 x 7 x 1) = 91 cm³ .

The question wants me to assume that the density of my calculator
is about  the same as the density of water.  That doesn't seem right
to me.  I could check it easily.  All I have to do is put my calculator
into water, watch to see if sinks or floats, and how enthusiastically. 
I won't do that.  I'll accept the assumption.

If its density is actually 1 g/cm³, then its mass is about 91 grams.

The choices of answers confused me at first, until I realized that
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My result of 91 grams is about 100 grams ... about 10² grams.

Your results could be different.
3 0
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