A block of material of volume 20cm-3 and density 2.5gcm-3 is suspended from a spring balance with half the volume immersed in water. What is the reading of the spring balance? (Density of water = 1.0gcm-3).
- 8g
- 25g
- 30g
-
40g
- 50g
The correct answer is: D
Explanation
W = pvg = (2.5 x 10 x 60)/100 = 0.500N.Upthrust = wt of liquid displaced = pvg water.
pvg water = (1x20x10)/2 = 0.10N
Reading => 0.500N - 0.100N = 0.4N = 40g