The boom of a fire truck raises a fireman (and his equipment – total weight 280 lbs) 60 ft into the air to fight a building fire. (a) showing all your work and using unity conversion ratios, calculate the work done by the boom on the fireman in units of btu. (b) if the useful power supplied by the boom to lift the fireman is 3.50 hp, estimate how long it takes to lift the fireman

Explanation:

Given that,

Weight = 280 lbs

Height = 60 ft

Power = 3.50 hp

(a). We need to calculate the work done by the boom on the fireman

Using formula of work done

Put the value into the formula

The work done by the boom is 21.59 Btu.

(b). We know that,

1 hp = 550 ft lbf

So,

We need to calculate the time

Using formula of time

Put the value into the formula

The time is 8.7 sec.

Hence, This is the required solution.

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =

answer a fan shaped mass of sediment deposited at the base of a mountain front do to an abrupt change in stream gradient;