Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
A plank is resting on a horizontal ground in the northern hemisphere of the Earth at a $45^{\circ}$ latitude. Let the angular speed of the Earth be $\omega$ and its radius $r_{e}$. The magnitude of the frictional force on the plank will be
PhysicsRotational MotionKVPYKVPY 2013 (SB/SX)
Options:
  • A $\mathrm{mr}_{\mathrm{e}} \omega^{2}$
  • B $\frac{\mathrm{mr}_{\mathrm{e}} \omega^{2}}{\sqrt{2}}$
  • C $\frac{\mathrm{mr}_{\mathrm{e}} \omega^{2}}{2}$
  • D Zero
Solution:
1314 Upvotes Verified Answer
The correct answer is: $\frac{\mathrm{mr}_{\mathrm{e}} \omega^{2}}{2}$


$\mathrm{F}_{5}=\mathrm{m} \omega^{2} r \cos 45^{\circ}$
where $r=\operatorname{Rcos} 45^{\circ}$
$\mathrm{F}_{\mathrm{r}}=\frac{\mathrm{m} \omega^{2} \mathrm{R}}{2}$

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.