Question

5.
00
The linear momentum of a particle moving
in X - Y plans under the influence of a
force is given as P (1) = A (i cos bt- sin bt)
where A and b are constants. The angle
between the force and momentum is
(A) 0°
(B) 45°
(C) 60°
(D) 90°​

Answer 1

Answer is given in the pic.

And solve my question.

Answer 2

Answer:

D) 90

Explanation:

P(t) = A [j˄ cos kt – j˄ sin kt]

F = [{dp(t)} / {dt}]

F = (d / dt) A [i˄ cos kt – j˄ sin kt]

= A [– i˄ sin kt (k)– j cos kt (k)]

F = Ak [– i˄ sin kt – j˄ cos kt]

angle between two vectors is θ

cos θ = {(F ∙ P) / (|F| |P|)}

= A [{(j˄ cos kt – j˄ sin kt) ∙ Ak (– i˄ sin kt – j˄ cos kt)} / {|F||P|}]

= A2 k [{– sin kt cos kt + sin kt cos kt} / {|F| |P|}]

= A2k(0) = 0

= θ cos–1(0)

θ = 90°

.......

hope it will help u ✌️✌️