MCQ
The work done to raise a mass $\mathrm{m}$ from the surface of the earth to a height $\mathrm{h}$, which is equal to the radius of the earth, is
- A$\mathrm{mgR}$
- B${2} \mathrm{mgR}$
- ✓$\frac{1}{2} \mathrm{mgR}$
- D$\frac{3}{2} \mathrm{mgR}$
✓
Answer
Correct option: C.
$\frac{1}{2} \mathrm{mgR}$
c
$\mathrm{W}=\frac{\mathrm{mgh}}{1+\mathrm{h} / \mathrm{R}}$
$\mathrm{W}=\frac{\mathrm{mgh}}{1+\mathrm{h} / \mathrm{R}}$
at $\mathrm{h}=\mathrm{R}, \mathrm{W}=\frac{\mathrm{mgR}}{2}$
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