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A particle moves in the X-Y plane under the influence of a force such that it's linear momentum is P(t)= A[ i cos(kt) - j sin(kt)] , where A and k are constants. The angle between the force and the momentum is (a) 0 (b) 30 (c) 45 (d) 90?
Verified Answer
A particle moves in the X-Y plane under the influence of a force such ...
Ans.

Option (d)

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
|}]
= A
2
 k [{– sin 
kt
 
cos
 
kt
 + sin 
kt
 
cos
 
kt
} / {|
F
| |
P
|}]
 = A
2
k(0)
= 0
θ = cos
–1
(0)
θ = 90�   
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Most Upvoted Answer
A particle moves in the X-Y plane under the influence of a force such ...
Analysis:
To determine the angle between the force and the momentum, we need to find the dot product of the force and momentum vectors. The dot product is given by the formula:

P(t) · F(t) = |P(t)||F(t)|cosθ

where P(t) is the momentum vector, F(t) is the force vector, and θ is the angle between them.

Finding the Force Vector:
The force vector can be determined by taking the derivative of the momentum vector with respect to time. Differentiating P(t) with respect to t, we get:

dP(t)/dt = -A[ i k sin(kt) + j k cos(kt)]

This is the force vector F(t).

Finding the Dot Product:
Now, we can find the dot product of the momentum and force vectors:

P(t) · F(t) = A[ i cos(kt) - j sin(kt)] · [-A( i k sin(kt) + j k cos(kt))]

Simplifying the dot product, we get:

P(t) · F(t) = -A^2[k cos^2(kt) + k sin^2(kt)]

P(t) · F(t) = -A^2k[cos^2(kt) + sin^2(kt)]

P(t) · F(t) = -A^2k

Angle between Force and Momentum:
The dot product of two vectors is equal to the product of their magnitudes and the cosine of the angle between them. Therefore, from the dot product equation:

P(t) · F(t) = |P(t)||F(t)|cosθ

we can see that if the dot product is negative, the angle between the vectors is 90 degrees (option d). If the dot product is positive, the angle is 0 degrees (option a). If the dot product is zero, the angle is 90 degrees (option d).

From the dot product we found earlier:

P(t) · F(t) = -A^2k

Since A and k are positive constants, the dot product is negative. Therefore, the angle between the force and momentum is 90 degrees (option d).

Conclusion:
The angle between the force and momentum is 90 degrees (option d).
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A particle moves in the X-Y plane under the influence of a force such that it's linear momentum is P(t)= A[ i cos(kt) - j sin(kt)] , where A and k are constants. The angle between the force and the momentum is (a) 0 (b) 30 (c) 45 (d) 90?
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A particle moves in the X-Y plane under the influence of a force such that it's linear momentum is P(t)= A[ i cos(kt) - j sin(kt)] , where A and k are constants. The angle between the force and the momentum is (a) 0 (b) 30 (c) 45 (d) 90? for Class 11 2024 is part of Class 11 preparation. The Question and answers have been prepared according to the Class 11 exam syllabus. Information about A particle moves in the X-Y plane under the influence of a force such that it's linear momentum is P(t)= A[ i cos(kt) - j sin(kt)] , where A and k are constants. The angle between the force and the momentum is (a) 0 (b) 30 (c) 45 (d) 90? covers all topics & solutions for Class 11 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A particle moves in the X-Y plane under the influence of a force such that it's linear momentum is P(t)= A[ i cos(kt) - j sin(kt)] , where A and k are constants. The angle between the force and the momentum is (a) 0 (b) 30 (c) 45 (d) 90?.
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