Question

1st. What is the relationship between force and speed?
2nd. When do the forces acting on an object add up?

Answer 1

The first law states that an object will stay at rest or move with a constant velocity, unless it is acted upon by an external force. The third is the well-known (if mildly misunderstood) idea that every action (force) has an equal but opposite reaction – if you push on a door, the door will push back against you.
The second law is the one that tells you how to calculate the value of a force. Force (measured in Newtons) is one of the fundamental physical properties of a system and comes in many forms. You might feel it as a push or pull (a mechanical force), while it is the value of your weight (the gravitational force of the Earth pulling on you) and can be seen in the repulsion or attraction of magnets or electric charges (electromagnetic force). A force might be the result of any number of fundamental physical interactions between bits of matter but Newton's second law allows you to work out how a force, when it is present, will affect the motion of an object. F= ma where( a=dv/dt)
when angle between F.S is 0°