Distinguish between an umbra and a penumbra?

Distinguish between an umbra and a penumbra .

Determine whether the polygons with the given vertices are similar. Support your answer by describing a transformation. A(3, 0), B(3, 6), C(9, 6), X(4, 0), Y(4, -8), Z(12, -8)

A man whose eye is 1.5 metres above ground level stands 20 metres from the base of a tree. The angle of elevation to the top of the tree is $45^{\circ}$. Calculate the height of the tree.

Do Earth and the Moon always cast shadows? What do we call the occurrence where one passes within the shadow of the other?

What do we mean when we say that outer space is not really empty?

Short wavelengths of visible light interact more frequently with the atoms in glass than do longer wavelengths. Which do you suppose takes the longer time to get through glass – red light or blue light?

What is the purpose of transmitting power at high voltages over long distances?

Why are metals shiny?

Why are metals shiny in appearance?

What is the purpose of a flagellum?

A parasail is attached by a 40-foot rope to the boat that is towing it. If the angle of elevation from the boat to the parasail is $34^{\circ}$, about how far above the water is the parasailer?

An accident reconstructionist takes measurements of the yaw marks at the scene of an accident. What is the radius of the curve if the middle ordlnate measures 5.3 feet when using a chord with a length of 39 feet? Round your answer to the nearest tenth of a foot.

It is now possible to buy capacitors that have a capacitance of one farad. Design a solenoid so that when it is connected to a charged 1 F capacitor, the circuit will oscillate with a period of one second. Give all the relevant parameters of the solenoid (length, etc.) so that someone could build the solenoid from your design specifications. Assume that there is wire available with low enough resistance that the resistance of the solenoid is negligible, although this may be difficult to achieve in practice unless the wire is superconducting.