Answer: 
Explanation:
Given
Diameter of the rod 
length of rod is 
Resistivity of silicon is 
cross-section of the rod 

Resistance of rod is R


Current is given by

300 divide 1.5=200 let me know if this was helpful
Explanation:
a) Density is the amount of mass in a specific amount of volume
b) Some substances are less dense than water so will float and vice versa
c) The wooden plank has less density than water due to having larger volume and vice versa with the wooden block since volume and density are inversely proportional
II) (a) They are all metals
(b) water -> Compound
oxygen -> Element
Gold-> Element
Salt-> Compound
B) Hope it helps ,Have a nice day :)
Answer:
The mass of the other worker is 45 kg
Explanation:
The given parameters are;
The gravitational potential energy of one construction worker = The gravitational potential energy of the other construction worker
The mass of the lighter construction worker, m₁ = 90 kg
The height level of the lighter construction worker's location = h₁
The height level of the other construction worker's location = h₂ = 2·h₁
The gravitational potential energy, P.E., is given as follows;
P.E. = m·g·h
Where;
m = The mass of the object at height
g = The acceleration due to gravity
h = The height at which is located
Let P.E.₁ represent the gravitational potential energy of one construction worker and let P.E.₂ represent the gravitational potential energy of the other construction worker
We have;
P.E.₁ = P.E.₂
Therefore;
m₁·g·h₁ = m₂·g·h₂
h₂ = 2·h₁
We have;
m₁·g·h₁ = m₂·g·2·h₁
m₁ = 2·m₂
90 kg = 2 × m₂
m₂ = (90 kg)/2 = 45 kg
The mass of the other construction worker is 45 kg.