Which objects play the roles of the sun earth and moon

Suppose air resistance does not exist, roughly what would be the velocity of a 10 lb object 5-seconds into free fall off of a 500-m building? How is this answer 50 m/s?

Describe the relationship between joules, meters, and newtons

Four identical metallic objects carry the following charges: + 1.51, + 6.28, - 4.69, and - 9.07C. The objects are brought simultaneously into contact, so that each touches the others. Then they are separated.

5. A certain spring that obeys Hooke's Law stretches 30 cm when a load of 0.35 N is added to it. How much energy is stored in the spring when it is compressed 5.0 cm?

17. 1 micrometer (1 µm) equals: A. 10-^3 m B. 10-^6 m C. 10^3 m D. 10^6 m

A boulder on top of a cliff has a potential energy of 12400J. How high above is the boulder?

If the graph represents speed what is measured on the x and y axes

It is difficult to lift a heavy stone than the lighter one on the earth, why?

The vapor pressure of ethanol at 25 degrees C is 7.83 kPa. Calculate the vapor pressure in atm. Round answer to 3 significant digits.

According to Newton's second law of motion acceleration or an object depends upon the ___ of the object and the ___ Acting on it. I'm confused on what the blanks are. I can't find them.