Register to reply

Grade 12 Physics - Circular Motion - Universal Gravitation

Share this thread:
synchrostarr
#1
Oct20-13, 10:00 AM
P: 1
1. The problem statement, all variables and given/known data

This question is from the Nelson Grade 12 Physics textbook.

The force of attraction between masses m1 and m2 is 26N in magnitude. What will the magnitude of the force become if m2
is tripled, and the distance between m2 and m1 is halved?

2. Relevant equations

FG=(Gm1m2)/r2

G=6.67x10-11

3. The attempt at a solution

I tried to look at both equations, the original and the altered equation so I had:

26N=(Gm1m2)/r2

and then for the changed equation I had"

FG=(Gm13m2)/(1/2)(r2)

But I was unable to figure out what to do from there.

If it is at all helpful, the answers in the back of my textbook said that the correct answer is 3.1x102N.
Phys.Org News Partner Science news on Phys.org
Bees able to spot which flowers offer best rewards before landing
Classic Lewis Carroll character inspires new ecological model
When cooperation counts: Researchers find sperm benefit from grouping together in mice
gneill
#2
Oct20-13, 10:37 AM
Mentor
P: 11,625
Quote Quote by synchrostarr View Post
1. The problem statement, all variables and given/known data

This question is from the Nelson Grade 12 Physics textbook.

The force of attraction between masses m1 and m2 is 26N in magnitude. What will the magnitude of the force become if m2
is tripled, and the distance between m2 and m1 is halved?

2. Relevant equations

FG=(Gm1m2)/r2

G=6.67x10-11

3. The attempt at a solution

I tried to look at both equations, the original and the altered equation so I had:

26N=(Gm1m2)/r2

and then for the changed equation I had"

FG=(Gm13m2)/(1/2)(r2)

But I was unable to figure out what to do from there.

If it is at all helpful, the answers in the back of my textbook said that the correct answer is 3.1x102N.
Hi synchrostarr, Welcome to Physics Forums.

You're on the right track. Note that if you halve the distance then the "1/2" applies to r, not to r2.

After you insert the changes into the formula, see if you can't factor them out so you end up with something like:

Fnew = C x (Gm1m2)/r2


Register to reply

Related Discussions
Circular Motion and Universal Law of Gravitation Help! Introductory Physics Homework 7
Circular Motion and Universal Law of Gravitation Homework help Introductory Physics Homework 1
Circular Motion and Universal Law of Gravitation Solutions Check Requested! Introductory Physics Homework 1
Circular Motion and Universal Gravitation Introductory Physics Homework 1
Circular Motion & Universal Gravitation: Gravity Between Introductory Physics Homework 1