Hi, I'm having some trouble doing my homework for Physics. I would appreciate it if anybody would help me or lead me in the right direction. Thank you. 1. Gas is confined in a tank at a pressure of 1.0x18^8 Pa and a temperature of 15.0 degrees Celcius. If half the gas is withdrawm and the temperature is raised to 65.0 degrees Celcius, what is the new pressure in the tank in Pa? ---Normally for problems such as these, I use the prportion of (P1V1)/T1 = (P2V2)/T2. But I don't know how to solve without the volume. Is there a way I couild find the volume, or do I have to use a different forumla? 2. A 5450-m^3 blimp circles Fenway Park duing the World Series, suspended in the earth's 1.21-kg/m^3 atmosphere. The density of the helium in the blimp is 0.178 kg/m^3. A) What is the buoyant force that suspends the blimp in the air? B) How does this buotant force compare to the blimp's weight? c) How much weight, in addition to the helium, can the blimp carry and still continue to maintain a constant altitude? ---I solved for a and for the answer 9.5x10^3 N by using the boyant force formula = D*g*v. However, I don't know what to do on b and c. 3. Allegra's favorite ride at the Barrel-O-Fun Amusement Park is the Flying Umbrella, which is lifted by a hydraulic jack. The operator activates the ride by applying a forcce of 72 N to a 3.0-cm-wide cylindrical piston, which holds the 20000. N ride off the ground. What is the diameter of the piston that holds the ride? ---Well honestly, for this problem, I have no idea where to start or do. n_n Thank you! Anything helps and is appreciated.