Verified Solution • 2025–26 Session moderate

QJEEM21Ph6aa5: JEE Main 2021 Physics - Class 11 JEEM21Ph6aa5 Solution: A block of 200 g mass moves with a uniform speed in a…

A block of 200 g mass moves with a uniform speed in a horizontal circular groove, with vertical side walls of radius 20 cm. If the block takes 40 s to complete one round, the normal force by the side walls of the groove is :

Multiple Choice Options

  • A 9.859 ×\times 10 −- 2 N
  • B 0.0314 N
  • C 9.859 ×\times 10 −- 4 N
  • D 6.28 ×\times 10 −- 3 N

Step-by-Step Verified Solution

Normal force will provide the necessary centripetal force.

⇒\Rightarrow N = m ω\omega 2R

Also, ω\omega = 2πt{{2\pi } \over t}

N = (0.2) (4π2T2)\left( {{{4{\pi ^2}} \over {{T^2}}}} \right) (0.2)

⇒\Rightarrow N = 0.2 ×\times 4×(3.14)2(40)2{{4 \times {{(3.14)}^2}} \over {{{(40)}^2}}} ×\times 0.2

∴\therefore N = 9.859 ×\times 10 −- 4 N

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