What’s the average acceleration of the particles between 0 seconds and 4 seconds

Light from the sun reaches the earth in 8.3 minutes. the velocity is 3.00 x 10^8 m/s. how far is earth from the sun? i know how to get to d = (3 x 10^8 m/s)(498 sec). i just don't know how to get from there to the answer being 1.5 x 10^11 m.

A2k pendulum has a speed of 1 m/s at a height of 1/2 meter

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?