Question

If an object with 1000 lb of weight is to be raised vertically from ground level to 5 ft in two seconds, how much power is required?

Answer 1

The power required = 3390.9 W

Step-by-step explanation:

Power: This can be defined as the time rate of doing work. The S.I unit of power is Joules.

Mathematically it can be expressed as,

P = Work/time or

P =W×V...................... Equation 1

Where P = power, w = weight, V = velocity.

Also

V = d/t ..................... Equation 2

Where d = distance, t = time.

Conversion: d = 5ft

If 1 foot = 0.3048 meters

Then, 5 ft = 5×0.3048 meters = 1.524 m.

W = 1000 lb

If 1 lb = 4.45 N,

Then 1000 lb = 1000× 4.45 N = 4450 N.

Given: d = 1.524 m, t = 2 s.

Substituting these values into equation 2

V = 1.524/2

V = 0.762 m/s.

Also substituting into equation 1

P = 4450×0.762

P = 3390.9 W.

Thus the power required = 3390.9 W