# I have two questions!

• Jul 6th 2006, 02:25 PM
Celia
I have two questions!
1.Which of the following in Not a unit of work?
a) W-s
b) N-m
c) kg-m/s
d) j
e) kw-h

2. To push a piece of heave furniture across the carpet usually takes more force to get it. moving that it takes to keep is moving. this is because.
a) the kinetic coefficient of friction is large that the static coefficient.
b) of newton's third law.
c) it does not take more force.
d) the static coefficient of friction is large than the kinetic coefficient.
• Jul 6th 2006, 04:30 PM
Soltras
I never was fond of physics.. but my best guesses would be C and D, respectively.

C for the first one because kg m/s is mass times velocity, which is force times time, but the unit of energy should be force times distance.

D for the second one because I remember something about something like that from physics class back in the day.

I reserve the right to be wrong since, like I said, I'm not a physics type of person... but those are my educated guesses.
• Jul 6th 2006, 08:26 PM
CaptainBlack
Quote:

Originally Posted by Soltras
I never was fond of physics.. but my best guesses would be C and D, respectively.

C for the first one because kg m/s is mass times velocity, which is force times time, but the unit of energy should be force times distance.

D for the second one because I remember something about something like that from physics class back in the day.

I reserve the right to be wrong since, like I said, I'm not a physics type of person... but those are my educated guesses.

D is joules which are the same thing as N-m, and so is a unit of work.

RonL
• Jul 6th 2006, 09:20 PM
Soltras
Yup that's why I'm pretty sure about the first one being C, and the second question being D. :cool:
• Jul 6th 2006, 11:29 PM
CaptainBlack
Quote:

Originally Posted by Soltras
Yup that's why I'm pretty sure about the first one being C, and the second question being D. :cool:

Opps :o

RonL
• Jul 7th 2006, 04:06 AM
topsquark
Quote:

Originally Posted by Soltras
I never was fond of physics.. but my best guesses would be C and D, respectively.

C for the first one because kg m/s is mass times velocity, which is force times time, but the unit of energy should be force times distance.

D for the second one because I remember something about something like that from physics class back in the day.

I reserve the right to be wrong since, like I said, I'm not a physics type of person... but those are my educated guesses.

For the record, Soltras is correct. For problem 1, the unit in answer C is the unit for a momentum. For problem 2, most materials have a larger coefficient of static friction than kinetic friction (in fact I've never seen a larger coefficient of kinetic friction listed). The problem itself says that it takes more force to cause it to move than to keep it to move which says the same thing as answer D.

-Dan
• Jul 7th 2006, 08:49 AM
Celia
Thank you!
Quote:

Originally Posted by Soltras
I never was fond of physics.. but my best guesses would be C and D, respectively.

C for the first one because kg m/s is mass times velocity, which is force times time, but the unit of energy should be force times distance.

D for the second one because I remember something about something like that from physics class back in the day.

I reserve the right to be wrong since, like I said, I'm not a physics type of person... but those are my educated guesses.

I really want to thank you! :D