Which of the following statement(s) is/are true?
1. Forces in the same direction add up.
2. Two forces in opposite directions result in a net force which is equal to their difference and acts in the direction of the larger force.
3. Change in the direction of a force does not change its effect.
4. When more than one force is acting on an object, the net effect is due to resultant of all forces.
1, 2 and 4