A labour is throwing 12 bricks per min from the ground and these just reach the roof which is 3.3 meters high. ifthe weight of each bricks be 3.75 kg then find the horse power with which the labour is working.
Power is rate of work.
Work is force times displacement.
Force is weight of each brick under gravity. Measure weight in [kgf] (kilogram-force: the weight of 1[kg] in normal gravity).
The conversion rate to metric horsepower is: 1[hp] = 75 [kgf·m/s]
Use: P = Ws/t
Where:
(1/t) = 12[/min] = 0.2[/s]
s = 3.3[m]
W = 3.75[kgf]
12 bricks/min*(1min/60s)=0.2bricks/s
m=(3.75kg/brick)
F=mg=(3.75kg/brick)*9.8m/s^2=36.75N/brick
d=3.3m
Since Power=Work/t(s)=F*d/t
Power=(36.75N/brick)*(0.2bricks/s)*(3.3m)=24.3 W
***Bricks cancel leaving (N*m)/s
24.3 W*(1hp/745.70 W)=0.0325 hp
To find the horse power with which the labor is working, we first need to calculate the power exerted by the labor.
Power is defined as the amount of work done per unit of time. In this case, the work done is the energy required to lift the bricks to the roof.
The energy required to lift an object is given by the formula:
Energy = mass × gravity × height
Since each brick weighs 3.75 kg and the height is 3.3 meters, we can calculate the energy required to lift one brick as follows:
Energy = 3.75 kg × 9.8 m/s² × 3.3 m
Next, we need to determine the rate at which the labor is doing work. We are given that the labor throws 12 bricks per minute. Therefore, the labor is doing work at a rate of:
Work Rate = 12 bricks/minute
To convert the work rate to Watts, we use the relationship:
1 Watt = 1 Joule/second
Since there are 60 seconds in a minute, we can calculate the power exerted by the labor as follows:
Power = (Energy/minute) × (1 minute/60 seconds)
Finally, to convert the power from Watts to horsepower, we divide by the conversion factor:
1 horsepower = 745.7 Watts
Therefore, the horse power with which the labor is working can be calculated as:
Horse Power = Power (Watts) / 745.7
By plugging in the values and performing the calculations, you can determine the horse power with which the labor is working.