A spherical weather balloon is filled with hydrogen until its radius is 3.00 m. Its total mass including the instruments it carries is 15.0 kg. (a) Find the buoyant force acting on the balloon, assuming the density of air is 1.29 kg/m3 . (b) What is the net force acting on the balloon and its instruments after the balloon is released from the ground? (c) Why does the radius of the balloon tend to increase as it rises to higher altitude?

A solid cone made of unknown material is suspended from a scale. Before submersion, the scale reads 100 Newtons. After submersion in water the scale reads 88.0 N as shown below. (a) What is the force of buoyancy on the cone? (b) What weight of water is displaced by the cone? (c) What mass of water is displaced by the cone (in kg)? (d) What volume of water is displaced by the cone (in cubic meters)? (e) What is the volume of the cone (in m³)? (f) What is the mass density of the cone (in kg/m³)? (Density of water, p = 1000 kg/m³) 100 N 88.0 N

A spherical weather balloon is filled with hydrogen until its radius is 4.10 m. Its total mass including the instruments it carries is 17.0 kg. (a) Find the buoyant force acting on the balloon, assuming the density of air is 1.29 kg/m3. 3649.7 X KN (b) What is the net force acting on the balloon and its instruments after the balloon is released from the ground? 3492.9 X KN (c) Why does the radius of the balloon tend to increase as it rises to higher altitude? Because the external pressure decreases with increasing altitude.

A small jet airplane has a total wing area of 90.0 m2 and a mass of 8.88 104 kg (a) If this jet is in horizontal flight, determine the pressure difference between the lower and upper surfaces of the wings. (b) When the speed of air traveling over the wing is 227 m/s, determine the speed of air under the wing. Use 1.29 kg/m3 as the density of air. (c) Why do all aircraft have a maximum operational altitude?