







The angle of a countersunk screw 
20200119 

From Barbie: I need to be able to verify the angle used for the head of a countersunk screw.
I have the diameter of the head, diameter of the shank and height between the
two. I assume it would be considered a frustum.
For example:
A standard 90 degree metric flat head screw in an M2 diameter has a head diameter of 3.65mm,
the actual thread diameter is 1.98mm and the height of the head is 1.20mm.
How can I prove that it is a 90 degree angle? Answered by Harley Weston. 





Two sunflowers 
20150312 

From Maurice: Sam and sally planted two sunflowers.Each sunflower grows 1cm each day. Sally's sunflower is 4cm high. Sam's is 12cm high. How high will each sunflower be when Sam's sunflower is twice the height of Sally's? Answered by Penny Nom. 





A model of the sun and the Earth 
20140614 

From Lynn: There is a model of the sun that is 2 1/2 inches in diameter. This is the only clue we have! How far away is the earth from this model? Answered by Penny Nom. 





The angular elevation of the sun 
20120714 

From VINEET: WHAT IS ANGULAR ELEVATION OF THE SUM Answered by Penny Nom. 





Angle of elevation 
20101210 

From PANKAJ: angle of elevation of the sun perpendicular72 and base 88 find angle Answered by Penny Nom. 





A sundial on an elliptical cylinder 
20090722 

From Leo: I want to build a sundial where the shadow falls on an elliptical cylinder. I can
calculate the coordinates of the points on the cylinder that I want to mark.
My problem is that I will have to make the surface as a flat sheet and bend it
into an elliptical shape. However, I cannot work out a scheme to transfer
the coordinates I know into a distance that will work when I bend the shape.
Help! Answered by Robert Dawson. 





Speed of sunrise 
20070904 

From Robert: Facing west in a car, you are watching the sun rise (through the rear view mirror). It peaks the horizon, you take off driving. How fast would you have to drive, to see it rise again? Answered by Stephen La Rocque. 





Two puzzles 
20040713 

From Fred: A young man's car developed a flat tire while he was driving along a deserted street. He pulled over to the curb and did all the usual things; removed the hub cap; unscrewed the lugs and rested them carefully in the hub cap, jacked up the car. As he was putting the spare tire onto the axle he accidentally kicked the hub cap. The lugs rolled out, and all five of them rolled down a nearby grate. Peering through the bars of the grate the man thought he could see the lugs about 6 feet below in a shallow water puddle. He had a problem, how do you think he solved it?
It is noon, your lunch hour, but you can not go out because there is a terrific hailstorm. Turning on your radio you hear the weathercaster predict that the hail will change to rain and that it will pour all day today. How can you determine the sun will be shining in 36 hours? Justify your answer. Answered by Penny Nom. 





Sunshine? 
20030711 

From lori: It is noon, your lunch hour, but you cannot go out because there is a terrific hailstorm. Turning on your radio you hear the weathercaster predict that the hail will change to rain and that it will pour all day today. How can you determine whether the sun will be shining in 36 hours? Answered by Claude Tardif. 





Sunflower seeds 
20001009 

From A parent: Find the number of 3/4 pound of sunflower seeds that can be filled with 225 pounds of sunflower seeds Answered by Penny Nom. 





Why counterclockwise? 
20000221 

From Drew: Why do the numbers of quadrants in a graph increase in a counter clockwise pattern? Why aren't they numbered increasingly in a clockwise pattern? Answered by Chris Fisher. 





The diameter of the sun. 
19961029 

From Lynda Mow: What is the process for solving the following question? As viewed from earth, the sun subtends an angle of approx 32'. If the sun is 93,000,000 miles from earth, find the diameter of the sun. Answered by Penny Nom. 

