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AP EAMCET · PHYSICS · Motion In Two Dimensions

A wooden plank of mass 90 kg and length 3.3 m is floating on still water. A girl of mass 20 Kg walks from one end to the other end of the plank. The distance through which the plank moves is

  1. A 30 cm
  2. B 40 cm
  3. C 80 cm
  4. D 60 cm
Verified Solution

Answer & Solution

Correct Answer

(D) 60 cm

Step-by-step Solution

Detailed explanation

\(\mathrm{M}=90 \mathrm{~kg}, \mathrm{l}=3.3 \mathrm{~m}, \mathrm{~m}=20 \mathrm{~kg}\) The distance by which plank moves is given by \(\Delta \mathrm{r}=\left(\frac{\mathrm{m}}{\mathrm{M}+\mathrm{m}}\right) \mathrm{l}=\left(\frac{20}{20+90}\right) \times 3.3=60 \mathrm{~cm}\)