physics
posted by paro .
Many cultures around the world still use a simple weapon called a blowgun, a tube with a dart that fits tightly inside. A sharp breath into the end of the tube launches the dart. When exhaling forcefully, a healthy person can supply air at a gauge pressure of 6.0 kPa.
What force does this pressure exert on a dart in a 1.4cmdiameter tube?

Multiply the gauge pressure in Pascals (6000) by the tube's circular inner area cross section in square meters (pi D^2/4) to get the force in Newtons.
pi D^2/4 = 1.54*104 m^2
I get about 1 Newton, which is about 1/4 pound force. 
Use the equation Pressure = Force / Area. Solve the equation for Force to get Force = Pressure * Area. Now, just plug in the values. Force = 0.006 Pa * (pi)0.008^2. Notice you need to divide the radius (0.008 m), not the diameter, in the equation for the area of a circle. The answer is 1.21 N.
Respond to this Question
Similar Questions

physics
A 200g Nerf dart is shot from a dart gun with a kenetic energy of 3.60J. What was the initial speed of the dart? 
physics
A springloaded dart gun is used to shoot a dart straight up into the air, and the dart reaches a maximum height of 12 meters. If the spring is compressed only half as far the second time, how far up does the dart go this time (no … 
NU
The end of a thin glasswall tube with an inside diameter of 1mm is inserted into a reservoir of pure water with a temperature of 25 degree C. What is the surface tension (adhesoin) force on the water inside the tube? 
Physics
If it takes an average force of 5.4 N to push a 4.8g dart 5.4 cm into a dart gun, assuming the barrel is frictionless, how fast will the dart exit the gun? 
physics
A 15.0 kg dart is thrown horizontally into a dartboard. The thrower applies a 80.0 N force over a distance of 88.2 cm in order to propel the dart. a) Calculate the work done by the dart thrower. b) Determine the velocity of the dart. … 
AP Physics
A dart gun vertically launches a 25g dart 50 cm high. Determine the minimum energy stored in the spring when the dart gun was loaded. What would the qualitative bar graph and energy flow diagrams look like? 
phyics
A dart leaves the barrel of a blowgun at a speed v. The length of the blowgun barrel is L. Assume that the acceleration of the dart in the barrel is uniform. Find a time that the dart moves inside the barrel. Express your answer in … 
phyics
A dart leaves the barrel of a blowgun at a speed v. The length of the blowgun barrel is L. Assume that the acceleration of the dart in the barrel is uniform. a) Show that the dart moves inside the barrel for a time of 2L/v Express … 
physics
A dart leaves the barrel of a blowgun at a speed v. The length of the blowgun barrel is L. Assume that the acceleration of the dart in the barrel is uniform. If the darts exit speed is 17 m/s and the length of the blowgun is 1.10 m, … 
Math
A circular target of radius 11 cm is to be hit as a game. The dart board has three concentric circles inside the bigger board of radii 7, 9 and 10 cm respectively,dividing the board into four regions.If Sarthak shot the dart 121 times, …