Question

Weight of a body of mass m decreases by 1% when it is raised to height h above the earth's surface. If the body is taken to a depth h in a mine, change in its weight is

• A. 2% decrease
• B. 0.5% decrease
• C. 1% increase
• D. 0.5% increase

Answer 1

Answer: (B)

0.5% decrease

Answer 2

Percentage change in g when the body is raised to height $h$ , $\frac { \Delta g } { g } \times 100 \% = \frac { 2 h \times 100 } { R } = 1 \%$

Percentage change in g when the body is taken into depth d, $d = h$]

∴ Percentage decrease in weight $= \frac { 1 } { 2 } \left( \frac { 2 h } { R } \times 100 \right) = \frac { 1 } { 2 } ( 1 \% ) = 0.5 \%$ .