Alight shines from the top of a pole 50 ft high. a ball is dropped from the same height from a point 30 ft away from the light. how fast is the shadow of the ball moving along the ground 1 sec later? (assume the ball falls a distance s equals 16 t squared in t sec.)

Explanation:

Let x represents the horizontal distance between the shadow and the pole

s= s(t) = 16t^2, distance the ball falls in time t

Then we have

Also after t=1 sec ball traveled

s= 16× (1)^2 = 16 ft

we need find relation between x and s. So, we do that by using given similar triangles ( first one created by the foot of the pole, top of the pole and shadow of the ball. Second one by the ball, part of the ground that is 30 ft away from the light and the shadow of the ball) By using similarity of triangles we can say

⇒ x= 1500/s

Finally, differentiating the above equation we get

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.

-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