A helium balloon can just lift a load of 790 N. The skin of the balloon has a mass of 1.80 kg. What is the volume of the balloon?(the density of air is 1.29 kg/m³ and the density of helium is 0.179 kg/m³)

74.10 cubic meters

Explanation:

The weught of load, balloon and heilium equals the weight of air displaced.

We know that density is mass per unit volume hence mass is product of density and volume, m=dv where d is density and v is volume

Weight is product of mass and acceleration due to gravity, W=mg=mgv where g is acceleration due to gravity and m is mass. We take g to be 9.81 m/s2

Weight of load=790 N

Weight of ballon= mg= 1.8*9.81

Weight of helium=0.179*9.81*v

Weight of air displaced =1.29*9.81*v

790+(1.8*9.81)+(9.81*0.179*v)=1.29*9.81*v

(1.29-0.179)v*9.81=807.658

10.89891v=807.658

V=74.104474667650

Rounding off, the volume is 74.10 cubic meters

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation: