Posted by **sarsi** on Thursday, September 19, 2013 at 3:11am.

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.

- physics -
**Graham**, Thursday, September 19, 2013 at 3:32am
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]

- physics -
**Devron**, Thursday, September 19, 2013 at 3:39am
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

## Answer This Question

## Related Questions

- Physics - A laborer is throwing 12 bricks per min from the ground and these just...
- Math - Julia wants to build another garden wall, 10 bricks long and 3 bricks ...
- Math - Building Bricks A child is playing with building bricks like this one. He...
- math - bricks are stacked in 20 rows such that each row has a fixed number of ...
- physics - A brick weight 17.8N and is resting on the ground. Its dimensions are ...
- math (algerbra) - A bricklayer's assistant starts building a wall, laying 50 ...
- MATH - a pile of bricks has 85 bricks in the bottom row, 79 bricks in the second...
- Math - You plan to construct a brick wall measuring 4.5 m in length, 1.2 m high...
- Physics - What power is needed to lift a 358 crate of bricks from the ground to ...
- Math - A pile of bricks has 85 bricks in the bottom row, 81 bricks in the second...

More Related Questions