The spider is traveling in a circle with radius = 15cm
The circumference of any circle = <em>2 pi (radius)</em>
The circumference of the spider's path = 2 pi (15 cm) = 30 pi cm
The spider completes a trip around this path 78 times per minute.
Its speed, relative to you, is
(78) x (30 pi) cm/min =
2,340 pi cm/min = 7,351.33 cm/min =
<em> 73.5133 meter/min =</em>
<em>4.411 km/hr =</em>
<em>2.74 miles/hour
</em>(After the last appearance of pi,
all numbers are rounded.)<em>
</em>
Velocity includes direction
This isn't physics, it's biology but basically, when you breath in oxygen, the oxygen goes to the lungs which transfer it to the blood cells. The heart then pumps the blood cells round to the organs, muscles etc and the blood cells drop off the oxygen where necessary, they then pick up carbon dioxide and the heart pumps them to the lungs where the blood cells give the lungs the carbon dioxide and the lungs make you breath the carbon dioxide out (his is a very simplified explanation, I'm not a biologist)
The angle of reflection is 42 degrees because it says the angle of incidence is equal to the angle of reflection