How Does Applying 1 Newton of Force Affect an Object's Motion?

[Ellipses]

I understand that a Newton (N) is the "amount of force required to accelerate a one-kg object at 1 m/s^2", but what exactly does that mean?

If I apply 1N of force to a 1kg object, will it constantly accelerate if I continue to apply the 1N? E.g. If I apply 1N of force for 10 seconds, the object will be traveling at 10m/s.

Or, is it just that if I constantly apply 1N, the object will constantly travel at 1m/s?

Thank you for your time and help.

 

[Pengwuino]

Remember, Force = Mass * Acceleration, Acceleration = Rate of Change of Velocity. So what you have is effectively Force = Mass * Rate of Change of Velocity. So if you're applying a constant force, you get a constant change in velocity, so you should expect the velocity to be increasing constantly. Thus, you would see your object traveling at 10m/s after 10 seconds.

 

[jhae2.718]

If force is constant:
[tex]
\begin{align}
&F = ma \\
&F = m\frac{dv}{dt} \\
&\frac{F}{m} = a = \frac{dv}{dt} \\
&dv = a dt \\
&v(t) = \int a dt \\
&v(t) = at+v_0 \equiv \frac{F}{m}t+v_0
\end{align}
[/tex]
So, from Eq. (6), if force is constant, velocity will increase at a constant rate, as Pengwuino has already stated.

 

[Ellipses]

Thank you both kindly. It's cleared up in my head now. But, then, I have to ask: how do I keep an object going at a constant velocity? If I apply a force and then stop, the object will eventually stop due to friction. If I continue to apply the force, it will accelerate. So how do I keep velocity constant?

 

[russ_watters]

Friction is a force. To keep an object going at constant speed, you must have no force -- or balanced forces (no net force).

 

[Pengwuino]

Thank you both kindly. It's cleared up in my head now. But, then, I have to ask: how do I keep an object going at a constant velocity? If I apply a force and then stop, the object will eventually stop due to friction. If I continue to apply the force, it will accelerate. So how do I keep velocity constant?

So to add to what Russ said, in order to say, keep an airplane at a constant velocity, the engines must provide an equal amount of force in opposition to the friction caused by air resistance.

 

[mishrashubham]

So to add to what Russ said, in order to say, keep an airplane at a constant velocity, the engines must provide an equal amount of force in opposition to the friction caused by air resistance.

And also generate enough lift to counter gravity.

 

[JaredJames]

And also generate enough lift to counter gravity.

So an aircraft can't travel at constant velocity whilst on the ground?

 

[russ_watters]

The engines generate negligible lift in level flight.

 

[mishrashubham]

So an aircraft can't travel at constant velocity whilst on the ground?

Well it can; then the majority of the friction would be from the ground. When Pengwuino mentioned air resistance I imagined the plane to be flying in air.

 

[mishrashubham]

The engines generate negligible lift in level flight.

To maintain a level flight, lift has to cancel out gravity.

 

[JaredJames]

To maintain a level flight, lift has to cancel out gravity.

Lift is from the wings, not the engines.

The engines simply need to provide velocity, that is what allows the wings to produce lift.

 

[mishrashubham]

Lift is from the wings, not the engines.

The engines simply need to provide velocity, that is what allows the wings to produce lift.

True