1.1. Figure 1 shows two masses, $A$ and $B$, in a light scale-pan. Mass $A$ rests on top of mass $B$.

Mass $A$ has a mass of  700 grams  and mass $B$ has a mass of  900 grams. 

The scale-pan is attached to a vertical light inextensible string.

Using the string, the scale-pan is raised vertically with an acceleration of $0.7m{s}^{-2}.$

Find the tension in the string.

1.2. Find the magnitude of the force exerted on mass $A$ by mass $B$.

1.3. Find the magnitude of the force exerted on mass $B$ by mass $A$.

1.4. Find the force exerted on mass $B$ by the scale-pan.