Laws of Motion Summary
Newton's first law:
Newton's first law states that if a body is at rest or moving at a constant speed in a
straight line, it will remain at rest or keep moving in a straight line at constant speed
unless it is acted upon by a force.
∑F = 0
The large Σ (the Greek letter sigma) represents the vector sum of all the forces, or the net force,
acting on a body.
Newton's second law:
Newton's second law states that the acceleration of an object is directly proportional to
the net force acting on it inversely proportional to its mass.
∑F = ma
Newton's third law:
If two objects interact, the force F12 exerted by object 1 on object 2 is equal in
magnitude and opposite in direction to the force F21 exerted by object 2 on object 1:
F12 = – F21
Newton's first law:
Newton's first law states that if a body is at rest or moving at a constant speed in a
straight line, it will remain at rest or keep moving in a straight line at constant speed
unless it is acted upon by a force.
∑F = 0
The large Σ (the Greek letter sigma) represents the vector sum of all the forces, or the net force,
acting on a body.
Newton's second law:
Newton's second law states that the acceleration of an object is directly proportional to
the net force acting on it inversely proportional to its mass.
∑F = ma
Newton's third law:
If two objects interact, the force F12 exerted by object 1 on object 2 is equal in
magnitude and opposite in direction to the force F21 exerted by object 2 on object 1:
F12 = – F21
