Answer:
(a) 152.85 Nm
(b) 1528.5 Nm
Explanation:
According to the formula of power
P = τ ω
ω = 2 π f
(a) f = 2500 rpm = 2500 / 60 = 41.67 rps
So, 40 x 1000 = τ x 2 x 3.14 x 41.67
τ = 152.85 Nm
(b) f = 250 rpm = 250 / 60 = 4.167 rps
So, 40 x 1000 = τ x 2 x 3.14 x 4.167
τ = 1528.5 Nm
The complete sentence is:
A calorimeter directly measures changes in temperature in order to calculate specific heat.
In fact, the amount of energy acquired/released by a substance is directly proportional to its change in temperature due to the equation
where Q is the amount of energy, m is the mass of the substance, Cs is the specific heat of the substance and 
is the change in temperature. Therefore, by knowing Q, m and by measuring the change in temperature, it is possible to calculate Cs, the specific heat capacity of the substance.
Answer:
Cost of 1000 kilowatt hour = 6000 cents
Explanation:
Given that
Electricity cost is 6 cents per kilowatt hour.
And we have to found out the cost for one megawatt hour
We know that
1 kilowatt = 1000 watt
1 megawatt = = 1000000 watt
1 megawatt = 1000 kilowatt
1 megawatt hour = 1000 kilowatt hour
Given that cost of 1 kilowatt hour = 6 cents
So the cost of 1000 kilowatt hour = 6 x 1000 cents
Cost of 1000 kilowatt hour = 6000 cents
