What Is the Connection Between Force and Acceleration?

AI Thread Summary
The discussion focuses on the relationship between force and acceleration, emphasizing that a net force is required for an object to accelerate. Initially, a greater force is needed to start an object moving, but maintaining motion requires less force due to reduced friction. Once the net force equals zero, acceleration ceases, and the object continues at a constant speed. The conversation highlights Newton's laws, particularly that a net force is necessary to change an object's motion, while ongoing motion can occur without additional force if friction is countered. Understanding these principles clarifies the dynamics of motion and acceleration.
jamesabc
Messages
22
Reaction score
0
i was just wondering about the relationship between force and acceleration.

from what i have learned in school and at university is that when a force is applied to an object, the object is accelerated. But what i am a bit confused about is why objects accelerate.

this is what i think but am not sure if it is right. it takes a certain amount of force to start an object moving, but as soon as the object starts moving the force required to keep it moving is less than the force to get to start moving in the first place. so if the initial force is keep constant then there will be acceleration? but eventually the friction from air resistance or whatever will eventually work against the acceleration and acceleration will be zero.

is this right?
 
Physics news on Phys.org
As long as there is a net force on an object, it will accelerate.
 
But if you maintain a constant force and friction increases with velocity, eventually the friction force will be equal to the applied force so the net[\b] force will be 0 and there will no longer be any acceleration.
 
Doc Al said:
As long as there is a net force on an object, it will accelerate.

by net force do you mean force greater than the force to get the object moving? or something else?
 
jamesabc said:
by net force do you mean force greater than the force to get the object moving? or something else?
The net force on an object is the vector sum of all individual forces acting on the object. As long as that net force is non-zero, the object will accelerate. When the net force is zero, the acceleration is zero. (Newton's 2nd law.)

To start something moving (from rest) some kind of force is needed. Once that force is removed, or other forces (like friction) are added, such that the net force is zero, the object will continue moving in a straight line at constant speed. (Newton's 1st law.)

In other words: You need a net force to change an object's motion (get it moving, for example); but once it's moving, it does not require a net force to keep moving. Of course, if friction acts on the moving object, you need to keep pushing to maintain the motion. But your push merely acts to overcome friction, making the net force zero.
 

Thread 'Is calling fictitious forces not real just about terminology?'

Hi there, im studying nanoscience at the university in Basel. Today I looked at the topic of intertial and non-inertial reference frames and the existence of fictitious forces. I understand that you call forces real in physics if they appear in interplay. Meaning that a force is real when there is the "actio" partner to the "reactio" partner. If this condition is not satisfied the force is not real. I also understand that if you specifically look at non-inertial reference frames you can...
View full post »

Thread 'Derivation of Hamilton's Principle: Questions'

I have recently been really interested in the derivation of Hamiltons Principle. On my research I found that with the term ##m \cdot \frac{d}{dt} (\frac{dr}{dt} \cdot \delta r) = 0## (1) one may derivate ##\delta \int (T - V) dt = 0## (2). The derivation itself I understood quiet good, but what I don't understand is where the equation (1) came from, because in my research it was just given and not derived from anywhere. Does anybody know where (1) comes from or why from it the...
View full post »

Similar threads

B Zero acceleration = zero net force?
Replies
33
Views
2K
I What friction causes objects to decelerate?
Replies
21
Views
2K
B Need help understanding some concepts about friction
Replies
12
Views
2K
B What Happens When The Applied Force Equals the Static Friction Force?
Replies
2
Views
3K
Force to accelerate an object downward faster than g
Replies
3
Views
1K
I Why don't we "fly up" in an accelerating elevator?
Replies
11
Views
3K
Why Does Friction Provide Centripetal Acceleration in Circular Motion?
Replies
37
Views
4K
B How come friction can make a car turn?
Replies
10
Views
2K
About acceleration and mass....
Replies
5
Views
1K
I How do we analyze collisions involving accelerating objects?
Replies
4
Views
2K

Hot Threads

Recent Insights

Back
Top