# Need help visualizing what an object is doing with force applied

• preluderacer
In summary: So in summary, when an object is moving in a certain direction with a net force also going in that direction but decreasing in magnitude over time, its speed will eventually become constant due to the decrease in acceleration. In a vacuum, the object will maintain this constant velocity, but in a non-vacuum environment, external forces such as drag and friction will cause the object to slow down until its velocity reaches zero. The concept of momentum can be used to explain this, with the initial and final momentums being equal in the absence of external forces. However, in most cases, external forces will affect the final velocity, acting as a collision or impulse that changes the object's momentum.
preluderacer

## Homework Statement

If an object is moving in a certain direction, with the net force also going in that direction, but the magnitude of the force is decreasing with time as it goes along. What is the speed of the object doing?

## The Attempt at a Solution

Im inclined to think the speed of the object is going to become constant, because if an object is in motion in stays in motion, am I right? I can't quite picture this.

>>in motion in stays in motion
yeah if your in a vacuum.

F = ma;

so if your force is decreasing therefor you acceleration is decreasing, since your mass is static (conservation of mass)

your acceleration will decrease until it hits zero, and when it does than the velocity will be constant.

Ok I think I got you. Let's say I am not in a vacuum. If I push a shopping cart then let go, does it still experience a force in the direction a pushed it after i let go, or does it slow down because the backward force is greater than the forward force?

after you push an object (after you let go), the only force it experiences is external forces such as drag, friction, ect... which will slow it down until the velocity reaches zero.

So, if I am only talking about horizontal forces, the forward force just diminishes over time with not back force?

You can use momentum to describe this

P$$_{f}$$ - P$$_{i}$$ = $$\int$$ Fdt

if there are not external forces (vacuum for example) than the expression goes to

P$$_{f}$$ - P$$_{i}$$ = 0

P$$_{f}$$ = P$$_{i}$$

mV$$_{i}$$ = mV$$_{f}$$

masses cancel and your left with

$$_{i}$$ = V$$_{f}$$ (for no external forces)

But this is usually not the case, you usually have an outside force that will affect the final velocity

You can consider the force that moves the object as a collision, an impulse

Last edited:

## 1. What is force?

Force is a physical quantity that describes the interaction between two objects. It is a vector quantity, meaning it has both magnitude and direction.

## 2. How is force applied to an object?

Force can be applied to an object in various ways, such as pushing, pulling, or lifting. It can also be applied indirectly, such as through gravity or friction.

## 3. How does force affect an object's motion?

Force can change an object's motion in different ways depending on its magnitude and direction. It can cause an object to speed up, slow down, change direction, or remain at rest.

## 4. How can we visualize an object's motion with force applied?

One way to visualize an object's motion with force applied is by using free body diagrams. These diagrams show all the forces acting on an object and their relative magnitudes and directions.

## 5. How can we measure the force applied to an object?

Force can be measured using a device called a force meter or by using the equation F=ma, where F is force, m is mass, and a is acceleration. The unit of force is Newton (N).

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