1.9 Describe the effects of forces between bodies such as changes in speed, shape or direction

Forces can change the speed, shape or direction of an object or a series of objects. 

Shape
If you have a perfect square of clay that you spent the last 30 minutes working on (and is still wet, so you can mould it, of course) and your teacher sticks his finger through it, it will get squashed. The teacher has applied a force that has changed the shape of the object.

Speed
If an object is moving at a steady speed, the forces pulling it forward/backwards are balanced. If it accelerates, the force driving it forward is greater than the one pulling it back. If it decelerates, it's the other way around; the force pulling it back is greater than the force driving it forward

Direction
The object will move in the direction of the greatest force that is acting on the object. I.e. if there is a 5N force pulling to the right and a 2N force pulling to the left, the object will move to the right: It will move in the direction of the resultant force.