Effects of Forces

1. In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate, to change its moving direction, shape etc. A force has both magnitude and direction, making it a vector quantity.(1)

2. The usual symbol of force is F and its SI unit is Newton (N).

3. As mentioned, a force will be able to change the shape, size, state of motion, direction of motion, acceleration of an object or body.

4. In our daily lives, the effects of forces can be seen everywhere, from driving a car, pushing a trolley, riding a bicycle, swimming, jumping, flying, gliding, rolling and even when stopping a movement. 

5. A force is deemed to be balanced when a forces cancel out each other resulting in net zero force. A good example is during a tug-of-war competition when both sides of the opponents have the same pulling force resulting in no net movement.  When this happens the force is said to be balanced.

6. When a balanced force is acting on an object, the object will remain stationary or moving at a constant velocity. E.g car moving at a constant velocity and plane flying with a constant velocity. There is no acceleration. 

7. Hence, when a system is in unbalanced force, the object will experience acceleration. 

8. Bear in mind that there can be more than two forces acting on a body at a certain time. For example below are the forces acting on a car and plane.

9. The movement of the object depends on the direction of the force / forces that have higher magnitude,

(1) Wikipedia