The first one just confuses me because of the word in the brackets.(adsbygoogle = window.adsbygoogle || []).push({});

1. A 70kg boy stands 1.0 m away from a 60 kg girl. Find the force of attraction (gravitational) between them.

For this would I just sub the values into F=Gm1m2/r^2?

The second question is giving me a lot of problems.

2. How fast would the earth (r=6400km) have to be spinning befor a 100kg person would exert no force on a scale at the equator? Assume the earth is a perfect sphere and it's mass is 6.0 * 10^24 kg.

For this I took F=ma and subbed in a=4 (pi)^2 r / T^2. Then I made F=0 and solved for T, but my answer gave me a period of 44 hours. This can't be write since it would have to be spinning faster than 24 hours. Please help.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Help with Gravitation questions

**Physics Forums | Science Articles, Homework Help, Discussion**