Newton's Second Law of Motion in the form force = change in momentum / time

Newton’s Second Law of Motion in the form force = change in momentum / time

  • Understand the basic principle: Newton’s Second Law of Motion states that force is equal to the rate at which momentum changes with time. It’s written in formula form as F = Δp / Δt where F is the force, Δp is the change in momentum and Δt is the change in time.

  • Note the units: Force is measured in Newtons (N), time in seconds (s), and momentum in kilogramme metres per second (kg m/s). When calculating, be sure to keep all units consistent.

  • Know the definition: Momentum is an object’s mass in motion. It is the product of an object’s mass and velocity. This implies that a larger object moving at the same speed as a smaller one will have greater momentum.

  • Understand how to calculate momentum: Momentum (p) is calculated by multiplying the mass (m) of an object by its velocity (v). This is expressed in the formula p = m * v.

  • Relation to Newton’s First Law: The second law is an extension of the first, as it states that an unbalanced force (F) will cause a change in momentum (Δp). This change will occur over a period of time (Δt).

  • Effect of Force: When a force acts upon an object for a certain amount of time, it changes the object’s velocity, and hence its momentum. The greater the force and the longer it is applied, the more the momentum changes.

  • Impact of Mass: The same force will have a greater effect (change in momentum) on a smaller mass than on a bigger one. This implies that heavier objects require more force to change their momentum.

  • Use of Law in Real Life: Newton’s Second Law aids in understanding various concepts like motion under gravity, motion on an inclined plane, and the mechanics of collisions.

  • Practice Questions: From a stationary position, a 3kg object is pushed for 5s with a force of 20N. What is the object’s final momentum? Remember to use the formula F = Δp / Δt to find your answer. In this case, Δp = F * Δt.