upward force at terminal velocity

[sfpublic]

A 50 kg box falls at its terminal velocity of 70 m/s. At this point, what is the upward drag force, in newtons?

[swansont]

A 50 kg box falls at its terminal velocity of 70 m/s. At this point, what is the upward drag force, in newtons?

 

What do you know to be true of the net force at terminal velocity?

 

And what are the individual forces acting on the object under that circumstance?

[sfpublic]

What do you know to be true of the net force at terminal velocity?

 

And what are the individual forces acting on the object under that circumstance?

 

I know the forces of gravity and drag must be equal, but I don't know how to calculate them given only that info.

[swansont]

You don't know how to calculate the force due to the acceleration of gravity?

 

F = ma

 

m is given. What's a?

[sfpublic]

a is 0, but i assume there must be some upwards force. no?

[DrP]

a = the accelaration due to gravity. Here on earth it is about 9.8 m/s^2

[Neil9327]

A 50 kg box falls at its terminal velocity of 70 m/s. At this point, what is the upward drag force, in newtons?

 

When the object is falling at terminal velocity it is no longer accelerating downwards, but maintaining a constant downward speed. This means that the force acting on it by gravity in a downward direction (its weight) must be equally matched by the upward force on it by the air drag.

 

Its weight is F = ma = 50Kg * 9.8 m/s/s/ = 490 Newtons.

[traveler]

If the object is not increasing or decreasing velocity then the acceleration is zero.

[sfpublic]

When the object is falling at terminal velocity it is no longer accelerating downwards, but maintaining a constant downward speed. This means that the force acting on it by gravity in a downward direction (its weight) must be equally matched by the upward force on it by the air drag.

 

Its weight is F = ma = 50Kg * 9.8 m/s/s/ = 490 Newtons.

 

thanks