- #1

Abu

## Homework Statement

A 12.0-kg box is pushed along a horizontal surface by a 24-N force as illustrated in the diagram. The frictional force (kinetic) acting on the object is 6.0 N

A) What is the acceleration of the object

B) Calculate the value of the normal force acting on the object

C) If the 12.0-kg object then runs into a 4.0-kg object that increases the overall friction by 3.0 N, what is the new acceleration?

D)

**What force does the 4.0-kg object exert on the 12-kg object when the two are moving together? (Issue I am having)**

## Homework Equations

a = fnet/m

fnet = Force applied - Force of Friction

## The Attempt at a Solution

D)

Fnet = Force applied - Force of Friction

m*a = Force applied - Force of Friction

Force applied = m*a + Force of Friction

Force applied = 4*0.587 + (3 + -18.4)

Force applied = -13.052 N

The reasons why I chose those numbers:

- 4 is the mass of the object that is exerting the force on the 12kg object
- If they are moving together, then I need to use the acceleration found in part C, which is 0.587 (if you need me to show my work for that part I can)
- Assuming the force applied is to the right, and that right will be positive, then the frictional force which is opposing the 4kg's movement to the left will be positive
- the 18.4 N that is pushing the entire set of objects will be negative because it is pushing to the left