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MHT CET20192 May 2019Morning ShiftPhysicsMathematics in PhysicsActual

The resultant R → of P → and Q → is perpendicular to P → . Also P → = R → . The angle between P → and Q → is tan ⁡ 45 o = 1

Options

  1. A5 π 4
  2. B7 π 4
  3. Cπ 4
  4. D3 π 4

Correct answer

D. 3 π 4

Step-by-step solution

tan ⁡ 90 o = Q s i n θ P + Q c o s θ ⇒ P + Q c o s θ = 0 ⇒ c o s θ = - P Q …(1) ∵ R 2 = P 2 + Q 2 + 2 P Q cos ⁡ θ ∵ P = R ∴ - P Q = 1 2 c o s θ …(2) From (1) & (2) c o s θ = ± 1 2 ∴ θ = 3 π 4

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