sfpublic Posted September 17, 2008 Share Posted September 17, 2008 A 50 kg box falls at its terminal velocity of 70 m/s. At this point, what is the upward drag force, in newtons? Link to comment Share on other sites More sharing options...
swansont Posted September 17, 2008 Share Posted September 17, 2008 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? Link to comment Share on other sites More sharing options...
sfpublic Posted September 17, 2008 Author Share Posted September 17, 2008 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. Link to comment Share on other sites More sharing options...
swansont Posted September 17, 2008 Share Posted September 17, 2008 You don't know how to calculate the force due to the acceleration of gravity? F = ma m is given. What's a? Link to comment Share on other sites More sharing options...
sfpublic Posted September 17, 2008 Author Share Posted September 17, 2008 a is 0, but i assume there must be some upwards force. no? Link to comment Share on other sites More sharing options...
DrP Posted September 17, 2008 Share Posted September 17, 2008 a = the accelaration due to gravity. Here on earth it is about 9.8 m/s^2 Link to comment Share on other sites More sharing options...
Neil9327 Posted September 17, 2008 Share Posted September 17, 2008 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. Link to comment Share on other sites More sharing options...
traveler Posted September 17, 2008 Share Posted September 17, 2008 If the object is not increasing or decreasing velocity then the acceleration is zero. Link to comment Share on other sites More sharing options...
sfpublic Posted September 17, 2008 Author Share Posted September 17, 2008 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 Link to comment Share on other sites More sharing options...
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