Calculate the upthrust on an object of volume 50cm³ which is immersed in a liquid of density 103kgm−³ [g = 10ms−²]

A. 0.8N
B. 2.5N
C. 0.5N
D. 1.0N

Correct Answer:

Option C – 0.5N

Explanation

Upthrust = change in weight

density = mass/volume

Mass of liquid displaced = Density of Liquid × Volume;

= 10³×50×10^−6m³

= 0.05kg

(Note that the volume of 50cm³ was converted to m³ by multiplying by 10^6) i.e 50cm³=50×10^−6m³

Since mass displaced = 0.05kg

Upthrust = mg = 0.05 × 10

= 0.5N