Posted by **steph** on Saturday, September 14, 2013 at 2:43pm.

A lightbulb emits light that creates a shadow of a ball on a wall. If the radius of the ball is 12.3 cm, and the radius of the shadow is 29.5 cm, and the ball is 1.27 m away from the wall, how far is the lightbulb away from the wall? (For the present problem, you may assume that the light bulb is a"point source".)

- physics -
**Steve**, Saturday, September 14, 2013 at 4:05pm
view the setup from the side, with the line joining the light source and the center of the ball perpendicular to the wall.

Then, if the light is x cm away from the wall, using similar triangles,

x/29.5 = (x-127)/12.3

x = 217.8 cm

## Answer this Question

## Related Questions

- physics - A lightbulb emits light that creates a shadow of a ball on a wall. If ...
- math - A street light (light source) is 15 m above the ground. A ball is freely ...
- calc - A light is at the top of a pole 80ft high. A ball is dropped at the same ...
- calculus - A light is attached to the wall of a building 64 feet above the ...
- Math - a light shines from the top of a pole 50ft high. a ball is dropped from ...
- Physics - A ball is launched up an inclined wall by a spring. The spring has a ...
- Dynamics - A ball is launched up an inclined wall by a spring. The spring has a ...
- physics - a ball of radius 5cm is hung against the wall with an 8cm rope from ...
- algebra - the weight of a symetry ball varies directly with the cube of it's ...
- physics - A 220-g ball strikes a wall with a speed of 7.0 m/s and rebounds with ...

More Related Questions