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# Physics/Accelerating Moving Objects

Question
Does it take more force to accelerate a moving object in the same direction ; as compared to accelerating an object that is not moving , say on a track. The moving object lets say is moving on a track, and.the whole track is accelerated forward while the object continues to maintain its constant speed in relation to the track. Would it take more force to accelerate the track with the object moving on it?

Hello Richard,

First let me answer your first question: Does it take more force to accelerate a moving object in the same direction ; as compared to accelerating an object that is not moving?
If the mass of the object and the value of acceleration is to be the same, then the force required would be the same. That force is given by Newton's 2nd Law, which is generally written
F = m*a

Now let me state your example involving a track: Would it take more, less, or the same force to accelerate the track and the object with the object stationary on it or moving at constant speed on it?
The force would be the same in all 3 cases. In the reference system that the track is moving in, the object's velocity is increasing according to the kinematic formula
Vf = Vi + a*t
I assume the value of a is to be the same whether the initial velocity, Vi, is zero or not.
Therefore F = m*a.

I hope this helps,
Steve

Physics

Volunteer

#### Steve Johnson

##### Expertise

I would be delighted to help with questions up through the first year of college Physics. Particularly Electricity, Electronics and Newtonian Mechanics (motion, acceleration etc.). I decline questions on relativity and Atomic Physics. I also could discuss the Space Shuttle and space flight in general.

##### Experience

I have a BS in Physics and an MS in Electrical Engineering. I am retired now. My professional career was in Electrical Engineering with considerable time spent working with accelerometers, gyroscopes and flight dynamics (Physics related topics) while working on the Space Shuttle. I gave formal classroom lessons to technical co-workers periodically over a several year period.

Education/Credentials
BS Physics, North Dakota State University
MS Electrical Engineering, North Dakota State University