If the net force is increased by a factor of 2, then the acceleration is decreased by a factor of 2. If the net force is decreased by a factor of 3, then the acceleration is increased by a factor of 3. The original acceleration value will have to be changed by multiplying or dividing it by the same factor that the acceleration was changed. How can one use information about how mass has been altered to determine its effect upon the acceleration?
To be successful on this question, you will have to think about the meaning of the statement: the acceleration of an object is directly proportional to the net force which it experiences and inversely proportional to its mass.
Whatever change is made in the net force, the same change will be made to the acceleration. So if the net force is increased by a factor of 2, the acceleration will be increased by a factor of 2 that is, multiplied by 2. And whatever change is made in the object's mass, the opposite change will be made to the acceleration. So if the object mass is increased by a factor of 3, the acceleration will be decreased by a factor of 3 that is, divided by 3.
Thus two changes will have to be made to the original acceleration value - it will have to be multiplied or divided by two different factors. Take your time and think it through - that's what Minds On is all about. Physics Tutorial. My Cart Subscription Selection.
The Physics Classroom ». Your browser does not support the audio element. Please download and view here. Newton's Second Law The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object. Use these principles to carefully select the correct answer. Click the button below to play an audio file in a separate window.
How can inertia be measured? How can Newton's first law be a consequence of Newton's second law? How are inertia and mass related? How does inertia affect the motion of a puck? Does the law of inertia pertain to moving objects? See all questions in Newton's First Law.
Newton's first law of motion predicts the behavior of objects for which all existing forces are balanced. Objects at equilibrium the condition in which all forces balance will not accelerate. According to Newton, an object will only accelerate if there is a net or unbalanced force acting upon it. The presence of an unbalanced force will accelerate an object - changing its speed, its direction, or both its speed and direction.
Newton's second law of motion pertains to the behavior of objects for which all existing forces are not balanced. The second law states that the acceleration of an object is dependent upon two variables - the net force acting upon the object and the mass of the object. The acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object. As the force acting upon an object is increased, the acceleration of the object is increased.
As the mass of an object is increased, the acceleration of the object is decreased. The above equation is often rearranged to a more familiar form as shown below. The net force is equated to the product of the mass times the acceleration. In this entire discussion, the emphasis has been on the net force. The acceleration is directly proportional to the net force ; the net force equals mass times acceleration; the acceleration in the same direction as the net force ; an acceleration is produced by a net force.
It is important to remember this distinction. Do not use the value of merely "any 'ole force" in the above equation. It is the net force that is related to acceleration. As discussed in an earlier lesson , the net force is the vector sum of all the forces. If all the individual forces acting upon an object are known, then the net force can be determined.
If necessary, review this principle by returning to the practice questions in Lesson 2. Consistent with the above equation, a unit of force is equal to a unit of mass times a unit of acceleration.
By substituting standard metric units for force, mass, and acceleration into the above equation, the following unit equivalency can be written. The definition of the standard metric unit of force is stated by the above equation.
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