Monday

April 21, 2014

April 21, 2014

Posted by **john** on Tuesday, March 16, 2010 at 7:40pm.

i just found the weight of the rock in air by multiplying 100 kg by 9.8 and got 980 kg. but i don't know what to do next

- physics -
**bobpursley**, Tuesday, March 16, 2010 at 7:54pmNo. The question is what is the weight of the rock as compared to in air.

The weight of the rock under water is

Wuw= mg-volume*densitywater*g

The weight of the rock in air is mg

comparing them..

wuw/Wair= (mg-volume*densitywater*g)/mg

= 1-volume*densitywater/m)

but m is volume*densityrock

Wuw/Wair= 1-densitywater/densityrock

check that math

**Related Questions**

physics - an aluminum object has a mass of 27 kg & a density of 2700 kg/m^3. it ...

Physics - can someone check? Which has greater volume: 1 kg of gold or 1 kg of ...

Physics - A cylindrical metal can with a radius of 4.25 cm is floating upright ...

PHYSICS - A cylindrical metal can with a radius of 4.25 cm is floating upright ...

Physics help please! - A cylindrical metal can with a radius of 4.25 cm is ...

College Physics - Part A) A 2.2 kg rock is released from rest at the surface of ...

physics - find the apparent weight of a 18 cm by 12 cm by 6 cm block of concrete...

Physics - A hollow plastic spherical bobber of mass 0.005 kg and volume of 50 ...

physics - balloon filled with 1 liter of water (1000 cm^3) in equilibrium in a ...

College Physics - A 2.2 kg rock is released from rest at the surface of a pond 1...