A balloon filled with helium gas has an average density of rhob = 0.39 kg/m^3. The density of the air is about rhoa = 1.23 kg/m^3. The volume of the balloon is Vb = 0.066 m^3. The balloon is floating upward with acceleration a. Required:
a. Express the net force F on the balloon in terms of its weight W and the buoyancy force Fb on it, assuming upward is the positive direction.
b. Calculate the numerical value of the acceleration a in m/s^2.

The key to stability is feedback between the reservoir and the fluxes into and/or out of the reservoir. assume that the rate of outflow from a reservoir depends on the size of the reservoir according to the following relationship: outflow rate= k x (size of reservoir), where k is a constant. a reservoir of water has a volume of 5000 liters, and the rate of outflow at steady state is 25 liters per minute. what is k? (give both the numerical value and its units.) what is the residence time? what is the relationship between k and the residence time?

As seen in a us weather map, the h (or high) and l (or low) symbols indicate regions where surface air pressures are high or low, respectively, compared to surrounding areas. an h is plotted where the air pressure is highest and an l is plotted where the air pressure is lowest. proceeding outward and away from the center of a high pressure system, the air pressure "

Lacie kicks a football from ground level at a velocity of 13.9 m/s and at an angle of 25.0° to the ground. how long will the ball be in the air before it lands? round your answer to the nearest tenth. s how far will the football travel before it lands? round your answer to the nearest tenth. m