The block is sitting at rest on the floor. the normal force on
is 3.00 n. find the mass of the block.

Mass=0.305[kg]

Explanation:

The block is located on a surface, where no forces act on it, so it will remain at rest according to Newton's laws.

We can perform an analysis of forces on the y-axis (see the free body diagram) and in order to determine the equation to determine the mass of the body, we must remember that the value of a force influenced by gravity is equal to the product of mass by acceleration.

From this equation we can clear the value of the mass

Iam pretty sure its b but if im wrong sorry

Question was not very clear if there are specific answer choices tell me and i'll try to you more. hope this though2 laps is 1 min. we know that for each min she does two times the amount of laps. for 12 laps we can do 12/2 which does give us 12 laps in 6 mins not 16 mins.