on a bright, sunny day you can use a magnifying glass to burn wood by focusing sunlight onto it. the focused sunlight forms a small circular spot of light that heats the wood until it burns. why is the spot of light circular?

What is the orbital period of a spacecraft in a low orbit near the surface of mars? the radius of mars is 3.4×106m.

The chart shows the costs and shipping times for materials that a company needs to build a new product. which describes the best trade-off if the company needs to start building their product within the next two years? they should order the domestic materials because it is always best to choose the fastest shipping time. they should order the imported materials because it is always best to choose the lowest cost for materials. since the shipping time is longer, they should order the domestic materials because the additional cost is worth it to get the materials in time. even though the shipping time is longer, they should order the imported materials because they are less expensive and should arrive in plenty of time to build the product.

An object dropped from cliff falls with a constant acceleration of 10 metre per second square find its speed of two seconds after it was dropped