Answer:
a
Explanation:
because they are easily reduced and oxidised
To find the ratio of planetary speeds Va/Vb we need the orbital velocity formula:
V=√({G*M}/R), where G is the gravitational constant, M is the mass of the distant star and R is the distance of the planet from the star it is orbiting.
So Va/Vb=[√( {G*M}/Ra) ] / [√( {G*M}/Rb) ], in our case Ra = 7.8*Rb
Va/Vb=[ √( {G*M}/{7.8*Rb} ) ] / [√( {G*M}/Rb )], we put everything under one square root by the rule: (√a) / (√b) = √(a/b)
Va/Vb=√ [ { (G*M)/(7.8*Rb) } / { (G*M)/(Rb) } ], when we cancel out G, M and Rb we get:
Va/Vb=√(1/7.8)/(1/1)=√(1/7.8)=0.358 so the ratio of Va/Vb = 0.358.
not too sure on this one maybe to locate objects under water, to diagnose problems, to treat medical ailments
Answer:
R = 400 ohms.
Explanation: Voltage of the battery, V = 40 V. Current in the unknown resistor I = 100mA. Let R is the resistance of the resistor. It can be calculated using Ohm's law it gives the relationship between the voltage, resistance and current.. R = V/I. R = 40 V/10-¹A. R = 400 Ohm's. So, the value of the resistance of the resistor is 400 Ohm's
