Question

11.
A particle is projected with a speed u If after 2 seconds of projection it is found to be making an ang
with the horizontal and 0° after 3 sec, then:
(A) Angle of projection is tan-'(3)
(B) Angle of projection is tan-?(1/3)
(C) Speed of projection = 30.2 m/s (D) Speed of projection is 30 m/s
12
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Answer 1

Answer:

Tan⁻¹(3)

Explanation:

A particle is projected with a speed u If after 2 seconds of projection it is found to be making an ang  45

with the horizontal and 0° after 3 sec,

Let say Initial Velocity = V projected at angle α

after 3 sec angle with the horizontal = 0

=> Vsinα - 3g = 0

=> Vsinα = 30

after 2 sec Vertical velocity = Vsinα - 2g =  Vsinα - 20 = 30 - 20 = 10

Horizontal Velocity = Vcosα

=> tan(45°) = (Vsinα - 2g)/Vcosα

=> 1 = 10/Vcosα

=> Vcosα = 10

=> Vsinα/Vcosα = 30/10

=> Tanα = 3

=> α = Tan⁻¹(3)

Angle of projection is Tan⁻¹(3)

Tanα = 3

=> Sinα = 3/√(3² + 1²)  = 3/√10

Vsinα = 30

=> V3/√10 = 30

=> V = 10√10

=> V = 31.62 m/s

Answer 2

Answer:

(A)     Angle of projection is tan -¹(3)

Explanation:

That's just to long to get bruh.