Question

1. The reflector of a flashlight is in the shape of a parabloid of revolution. its diameter is 8 inches and its depth is 4 inches. how far from the vertex should the light bulb be placed so that the rays will be reflectes parallel to the axis?

place the light bulb ? inch(es) from the vertex

2.The Cables of a suspension bridge are in the shape of a parabola, as shown in pic below. the towers supporting the cable are 300 FT apart and 20 FT high. if the cables touch the road surface midway between the towers, what is the height of the cable at a point 75 ft from the center of the bridge?

The cable is ? FT from the road surface at a point 75 FT from the center of the bridge.

3. A mirror is shapes like a parabloid of revolution and will be used to concentrate the rays of the sun at its focus, creating a heat source (see figure below) If the mirror is 30FT accross at its opening and is 14 FT deep, where will the heat source be concentrated?

the heat source will be concentrated about ? FT above the bottom of the mirror( round to two decimal places)

Aminor is shaped iko a paraboloid dnevolution and wil be used to certat" he rays of the sun at its focus, creating a heat sonn (See the fgre)げ he mirror is 30 feet across at is opening and is 14 feet deep, where will the heat source be concentrate The heat source will be concentrated about feel above the bom of the mimor Round to two desimal places as needed) The coabies of a suspension bridge ane in the shape of a parabolia, as shown in the figure. The towers apart and 20 eet high if the cables touch the te mad surtace midway between the towers, what is the height of the cable at a point 75 feet from the center of the bridge 11.2.67 The reflector of a flashlight is in the shape of a paraboloid of nevolution Its diameter is 8 inches and ts depth is 4 inches. How far from the vertex should the light bulb be placed so Fat the rays wial be reecte Pace the ight bub□nches)from the vertex. eston Help parel to the axs 20 ft 75 ft 300 ft Sun's rays 30 14"

Answer 1

150,20 (150,20 -150,0 300t 1S0'2 4p20 p 2 281 258t (42) 7 2

Conte to,4-015) LB) The lost wil be concentnded abod 401sBt above the botton o8 the wiw*

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