Physics, 30.10.2019 20:31 aangishah8452

A0.0500-kg golf ball heads off from the tee with an initial speed of 78.2 m/s and reaches to its maximum height of 37.8 m. if air resistance is neglected, (a) what is the kinetic energy of the ball at the pinnacle of its trajectory? (b) what is its speed when it is 5.60 m below the pinnacle point?

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Answer from: 21gl13826

(a) 134.4 J

The total mechanical energy of the ball at the moment of launch is just equal to its initial kinetic energy:

$E=K_i = \frac{1}{2}mu^2$

where

m = 0.05 kg is the mass of the ball

u = 78.2 m/s is the initial speed

Substituting,

$E=\frac{1}{2}(0.05)(78.2)^2=152.9 J$

At the pinnacle of its trajectory, the total mechanical energy is sum of kinetic energy and potential energy:

E=K_f + U_f = K_f + mgh

where

g=9.8 m/s^2 is the acceleration of gravity

h = 37.8 m is the maximum height

Since the total energy must be conserved,

E = 152.9 J

Therefore, we can solve to find the kinetic energy of the ball at the pinnacle:

K_f = E-mgh=152.9-(0.05)(9.8)(37.8)=134.4 J

b) 74.2 m/s

When the ball is 5.60 m below the pinnacle point, the heigth of the ball is

h=37.8-5.6=32.2 m

So its potential energy is

U=mgh=(0.05)(9.8)(32.2)=15.8 J

The total energy is again the sum of potential and kinetic energy:

E = K + U

So the kinetic energy at that point is

K=E-U=152.9-15.8=137.1 J

And since the kinetic energy is

$K=\frac{1}{2}mv^2$

We can find the speed:

$v=\sqrt{\frac{2K}{m}}=\sqrt{\frac{2(137.1)}{0.05}}=74.2 m/s$

Answer from: Quest

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explanation:

Answer from: Quest

-first use of geothermal energy occurred more than 10,000 years ago in north america by american paleo-indians

-the first industrial use of geothermal energy began near pisa, italy in late 18th century

-in 1904, italian scientist piero ginori conti invented the first geothermal electric power plant in which steam was used to generate the power

-with the above experiment, the first geothermal plant in usa started in 1922 with a capacity of 250 kilowatts

-however, in 1946 first ground-source geothermal heat pump installed at commonwealth building in portland, oregon

-during the 1960’s, pacific gas and electric began operation of first large scale geothermal power plant in san francisco, producing 11 megawatts

-in 1973, when oil crisis began many countries began looking for renewable energy sources and by 1980’s geothermal heat pumps (ghp) started gaining popularity in order to reduce heating and cooling costs

-as effect of climate change started showing results, governments of various countries joined hands to fight against it, for which kyoto protocol was signed in japan in 1997, laid out emission targets for rich countries and required that they transfer funds and technology to developing countries, 184 countries have ratified it

hope this

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A0.0500-kg golf ball heads off from the tee with an initial speed of 78.2 m/s and reaches to its max...