): an object pulled to the right by two forces has an acceleration of 2.5 m/s2.

The first thing we must do for this case is the sum of forces in a horizontal direction.

We have then:

Substituting values we have:

From here, we clear the mass of the object:

We now look for the weight of the object.

Where,

g: acceleration of gravity (9.8 m/s^2)

Substituting values:

the weight of the object is:

option 4

2.56 years

Explanation:

Payback period calculates the amount of time it takes to recover the amount invested in a project from its cumulative cash flows.

payback period = amount invested / cash flows

cash flows = $510,000 - $360,000 = $150,000

$384,000 / $150,000 = 2.56 years