An object with true weight 60 N has apparent weight 40N inwater. Find (a) the bu
ID: 1728652 • Letter: A
Question
An object with true weight 60 N has apparent weight 40N inwater. Find (a) the buoyant force, (b) the specific gravity. (c)what is the apparent weight in water of a 500-gm peice of copper(specific gravity 9.0)? (d) If your true weight is 750 N, what isyour apparent weight in air?(Assume your body to have a denstiy1,000 kg/m^3 and calculate the buoyant force exerted on your bodyby the surround air). I got this question wrong on my homework. The teacher did notgive us the answer nor explain to us how to do it. He told us aquestion similar to do will be on the finals. I want to understandhow to do it so I won't get it wrong on the final. Can someoneplease help me solve this problem. An object with true weight 60 N has apparent weight 40N inwater. Find (a) the buoyant force, (b) the specific gravity. (c)what is the apparent weight in water of a 500-gm peice of copper(specific gravity 9.0)? (d) If your true weight is 750 N, what isyour apparent weight in air?(Assume your body to have a denstiy1,000 kg/m^3 and calculate the buoyant force exerted on your bodyby the surround air). I got this question wrong on my homework. The teacher did notgive us the answer nor explain to us how to do it. He told us aquestion similar to do will be on the finals. I want to understandhow to do it so I won't get it wrong on the final. Can someoneplease help me solve this problem.Explanation / Answer
from the given the object weight in air is W when it isimmersed in water the buoyant force B from the water reduces thetension in the string to T2 = W - B (a) so the buoyant force is the difference betweenthe first scale reading in air and the second scale reading inwater B = W - T2 = 60 N - 40 N = 20 N the specific gravity is defined by sg = density of material / density ofwater now here density of material is unknown to getit we follow that as the magnitude of the buoyant force is equalto the weight of the displaced fluid Wf we have that Wf = f gVf Vf is the volume of the displacedfluid and f is its density the volume of the object V is equal to thevolume of the displaced fluid Vf as it is in water V = Vf = 20 N / gf so the density of the object (material) willbe = m / V = W / g V = .......... kg /m3 now solve for the specific gravity in the similar manner solve for the piece ofcopper also in case of a man in general it is not correctly possible tocalculate the buoyant force on a man because the volume is the mainunknown thing and the density when an object or a body is totally submerged ina fluid (air in this case) then the buoyant force acting on it isgiven by B = fluid Vobj g fluid(air) = 1.29 kg /m3 g is acceleration due to gravity 9.80 m /s2 the volume V is the unknown thing here if we know the mass with help of weight we mustbe given with the density also