Please provide solutions so I can better understand them. Thank you

7. A 2-1-volt battery and a 1525-9 resistor are used to charge four 1525 Q capacitors. as shown. The capacitors C1. C3. C3. and C4 have values of 55.0 11544.0 ttF. l9.0 ttF. and 88.0 LIE respectively. +_| l (a) What is the equivalent capacitance? ~ (b) The switch is closed. What is the charging time constant? 8. A banjo string 0.35 meter long has a fundamental frequency of 725 Hz. What is the speed of a wave on this string? 9. A reversible adiabatic process is used to drive a H ywheel."A' piston whose area is" 0.465 ml. compresses air a distance of 0.155 m with a pressure of 17.300 pascals. What is the change in internal energy of the air in the cylinder? 10. The negative charge at A causes an electric eld on F as shown P and has a magnitude of L9 >1 107 newtons per coulomb. The 7 N charge at B is negative 3.4 x 10'6 coulomb. Find the electric 1'9 x 10 6 eld at P caused by the two charges. 50 cm 4.0 cm A G 0 8 3.0 cm