Physics Buffs, Can You Answer This?

Energy requirement is the same. In each case you are moving the same mass the same distance against gravity.

^What he said. Third grade science.

Theory says the same, but you would end up expending more energy lifting the smaller weights due to internal friction costs due to the greater number of repeated motions.

The second one because you'll be tired from the first lift.

markschultz25 wrote:

What takes more energy? Lifting one 20lb weight off the ground some distance, or lifting 2 10lb weights off the ground the same distance?

Also, explain to me how you came to your answer.

Your wording of the question is terrible.

The energy change on the weights is the same, pretty much by definition. The energy consumed by the person doing the lifting might not be the same because of differences in the efficiency of lifter.

The first one is a single lift, the second one requires two lifts with a negative in between.

If you are lifting the 20 lb weight with 1 hand you will need to generate some torque with your obliques to counteract the weights moment arm which would increase energy energy expenditure.

D3 wins wrote:

If you are lifting the 20 lb weight with 1 hand you will need to generate some torque with your obliques to counteract the weights moment arm which would increase energy energy expenditure.

The poorly worded question does not state you are lifting with your body. Could be using a crane, forklift, elevator, etc.

I also have a physics question which has bugged me for years. Please help.

If I have a perfectly rigid sphere, and I place it on a perfectly rigid plane, what is the area of the point at which they intersect?

Another way to think about this is, if i take my sphere and dip it in paint, then place it on the plane, what is the size of the paint dot left on the plane?

Ashton Eating wrote:

I also have a physics question which has bugged me for years. Please help.

If I have a perfectly rigid sphere, and I place it on a perfectly rigid plane, what is the area of the point at which they intersect?

Another way to think about this is, if i take my sphere and dip it in paint, then place it on the plane, what is the size of the paint dot left on the plane?

Another question:

If I have a perfectly insulated box with mirrors on the inside, and a lightbulb inside the box, if I close the box, turn on the lightbulb, and then turn off the lightbulb, when I open the box will it release light?

Ashton Eating wrote:

I also have a physics question which has bugged me for years. Please help.

If I have a perfectly rigid sphere, and I place it on a perfectly rigid plane, what is the area of the point at which they intersect?

Another way to think about this is, if i take my sphere and dip it in paint, then place it on the plane, what is the size of the paint dot left on the plane?

This is not a physics question.

Would need to know the area of the sphere.

If you add paint into the problem, then it becomes a third surface or shape or whatever, so the viscosity of the liquid and the total volume applied to the sphere would have some bearing on the size of the dot.

Ashton Eating wrote:

Ashton Eating wrote:

I also have a physics question which has bugged me for years. Please help.

If I have a perfectly rigid sphere, and I place it on a perfectly rigid plane, what is the area of the point at which they intersect?

Another way to think about this is, if i take my sphere and dip it in paint, then place it on the plane, what is the size of the paint dot left on the plane?

Another question:

If I have a perfectly insulated box with mirrors on the inside, and a lightbulb inside the box, if I close the box, turn on the lightbulb, and then turn off the lightbulb, when I open the box will it release light?

Last time I tried this:

Ashton Eating wrote:

Another question:

If I have a perfectly insulated box with mirrors on the inside, and a lightbulb inside the box, if I close the box, turn on the lightbulb, and then turn off the lightbulb, when I open the box will it release light?

Ashton Eating wrote:

I also have a physics question which has bugged me for years. Please help.

If I have a perfectly rigid sphere, and I place it on a perfectly rigid plane, what is the area of the point at which they intersect?

Another way to think about this is, if i take my sphere and dip it in paint, then place it on the plane, what is the size of the paint dot left on the plane?

It will be a blob of paint that depends on how runny it is and how deep you dip it in the paint initially.

Ashton Eating wrote:

Ashton Eating wrote:

I also have a physics question which has bugged me for years. Please help.

If I have a perfectly rigid sphere, and I place it on a perfectly rigid plane, what is the area of the point at which they intersect?

Another way to think about this is, if i take my sphere and dip it in paint, then place it on the plane, what is the size of the paint dot left on the plane?

Another question:

If I have a perfectly insulated box with mirrors on the inside, and a lightbulb inside the box, if I close the box, turn on the lightbulb, and then turn off the lightbulb, when I open the box will it release light?

This is best simulated by performing a "dutch oven" in a polar sleeping bag.

Did someone call me?

dude work is just distance times force... so you would do 20 times x lbs= 20x... for the 10 lbs 2(10 times x) that gives you 20x... work is the same as energy

Ashton Eating wrote:

If I have a perfectly rigid sphere, and I place it on a perfectly rigid plane, what is the area of the point at which they intersect?

zero