# Can force be understood in terms of time/speed?

• jocose
In summary: I'll try to focus on a specific problem and clarify what I'm wondering about. What is happening when a force is applied continuously such as when I am holding an object in place. In the context of this conversation, this means that a force is being applied at a "rate".
jocose
If there is a massive object floating in space and I tap the side of it with a relatively small force it will move said object a very small amount.

If I tried the same thing on Earth the object would not move because of gravity. I'm inferring (perhaps erroneously) that this means the object is in fact moving but gravity is repositioning the object faster than I displace it?

If this is correct what would happen if I applied a small force very quickly. Would it be possible to outpace the speed at which gravity is moving the object back into position? Would a 1 Newton tap successively applied at an extremely fast rate equal a greater force?

I know F=MA and that acceleration is the rate of change. Is it there for paradoxical to view a force being applied at a rate as the rate is built into the definition?

What is happening when a force is applied continuously such as when I am holding an object in place. Is a force being applied at a "rate"?

I'm confused by this for some reason and if anyone could better characterize what a force is in relation to time I would appreciate it. I suspect its probably confusing for the same reason elastic collisions such as in Newtons cradle are counter intuitive as they deal with infinite quantities.

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I'm totally confused by virtually everything you've said. This doesn't sound like any kind of physics I've ever seen or heard of. Maybe you can pose a specific focusing problem involving the concepts you are wondering about, and we can help you work your way through it. Focusing problems are often an effective way of learning a subject.

jocose said:
If there is a massive object floating in space and I tap the side of it with a relatively small force it will move said object a very small amount.
It will accelerate the object a small amount -- it may then move forever.
If I tried the same thing on Earth the object would not move because of gravity.
That isn't true. Gravity does not prevent anything from moving (at least directly). Consider a book resting on a table. If you apply a small horizontal force to it and it doesn't move, what prevented it from moving? Not gravity: friction.

If you consider the vertical forces, still isn't gravity that keeps it from moving, it's the vertical force applied to the book by the table that keeps it from moving.
Is a force being applied at a "rate"?
Force doesn't have a rate -- but it can have a duration. A short tap is a short duration of applied force.

jocose
russ_watters said:
It will accelerate the object a small amount -- it may then move forever.

That isn't true. Gravity does not prevent anything from moving (at least directly). Consider a book resting on a table. If you apply a small horizontal force to it and it doesn't move, what prevented it from moving? Not gravity: friction.

If you consider the vertical forces, still isn't gravity that keeps it from moving, it's the vertical force applied to the book by the table that keeps it from moving.

Force doesn't have a rate -- but it can have a duration. A short tap is a short duration of applied force.
Thanks Russ,

This is helpful. I've mixed several things up. I apologize for being inarticulate but as you can tell I was very confused.

russ_watters

## 1. Can time affect the amount of force applied to an object?

Yes, time can affect the amount of force applied to an object. This is because force is defined as the rate of change of momentum, and momentum is directly proportional to an object's mass and velocity. So, the longer the time in which a force is applied, the greater the change in momentum and therefore the greater the force exerted on the object.

## 2. Is force related to the speed of an object?

Yes, force and speed are related. This is because force is the product of an object's mass and acceleration (F=ma), and acceleration is defined as the change in an object's velocity over time. So, the greater the speed of an object, the greater the force needed to change its velocity.

## 3. How does time affect the impact of a force on an object?

The impact of a force on an object is directly related to the time over which the force is applied. The longer the time of application, the less intense the impact of the force will be. This is because the force is spread out over a longer period of time, reducing its overall effect.

## 4. Can the speed of an object affect the force of impact?

Yes, the speed of an object can affect the force of impact. This is because force is directly proportional to an object's mass and acceleration. So, the greater the speed of an object, the greater its acceleration and therefore the greater the force of impact.

## 5. How does understanding time and speed help in calculating force?

Understanding the relationship between time, speed, and force is crucial in calculating force. This knowledge allows us to use equations such as F=ma or impulse-momentum theorem to calculate the force exerted on an object. By knowing an object's mass, velocity, and the time over which a force is applied, we can accurately calculate the force exerted on the object.

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