Calculating Minimum Horsepower Needed for Object Movement

[rm121181]

Homework Statement

If weight x distance over time equals work done. Work done divided by time will give me work done over time foot pounds. Foot pounds can be converted to horsepower. So I should be able to find minimum horse power needed to push
a known weight a known distance in a known time right? Am I missing something? It seems like my horsepower needed numbers are very high.

Homework Equations

The Attempt at a Solution

 

[drvrm]

If weight x distance over time equals work done. Work done divided by time will give me work done over time foot pounds. Foot pounds can be converted to horsepower. So I should be able to find minimum horse power needed to push

set up the problem

a known weight a known distance in a known time right? Am I missing something? It seems like my horsepower needed numbers are very high.

horse-power; is an unit of power equal to 550 foot-pounds per second (about 750 watts).

 

[haruspex]

weight x distance over time equals work done

No, weight x distance = work done; dividing that by time gives power.

work done over time foot pounds.

No idea what that means. The work done over the time a runner's foot pounds the pavement?

Foot pounds can be converted to horsepower.

No, foot pounds is a measure of work, not power.

 

[CWatters]

If weight x distance over time equals work done.

Only if the distance is vertical. The correct equation is..

Work = force * displacement

So I should be able to find minimum horse power needed to push
a known weight a known distance in a known time right?

No because the force required to move an object is not equal to the weight. For example the force might depend on friction, rolling resistance, air resistance etc some of those might be effected by weight but it might not be a simple relationship.