Q.

The position of a particle moving on x-axis is given by x(t) = A sin t + B cos2t + Ct2 + D, where t is time. The dimension of ABCD is-

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a

L

b

L2

c

L3 T–2

d

L2 T–2

answer is C.

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Detailed Solution

We are given the position function of a particle moving along the x-axis:

x(t)=Asint+Bcos2t+Ct2+Dx(t) = A \sin t + B \cos^2 t + C t^2 + D

where xx represents position, and tt is time.

We need to determine the dimension of ABCD\frac{ABC}{D}.

Step 1: Identify Dimensions of Each Term

Since all terms in the given equation represent position (xx), they must have the same dimensional formula as length [L][L].

1st Term: AsintA \sin t

  • sint\sin t is dimensionless.
  • So, AA must have the same dimension as xx, which is LL.

[A]=[L][A] = [L]

2nd Term: Bcos2tB \cos^2 t

  • cos2t\cos^2 t is dimensionless.
  • So, BB must also have the same dimension as xx, which is LL.

[B]=[L][B] = [L]

3rd Term: Ct2C t^2

  • t2t^2 has the dimension T2T^2.
  • Since Ct2C t^2 must have the dimension of length [L][L], we get:

[C]=[L][T]2=[LT2][C] = \frac{[L]}{[T]^2} = [L T^{-2}]

4th Term: DD

  • Since DD represents a position constant, it has the same dimension as xx, which is LL.

[D]=[L][D] = [L]

Step 2: Compute ABCD\frac{ABC}{D}

ABCD=([L])([L])([LT2])[L]\frac{ABC}{D} = \frac{([L])([L])([L T^{-2}])}{[L]}

Canceling [L] in the numerator and denominator:

[LLLT2]/[L]=L2T2[L \cdot L \cdot L T^{-2}] / [L] = L^2 T^{-2}

Thus, the dimension of ABCD\frac{ABC}{D} is [L2T2]

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The position of a particle moving on x-axis is given by x(t) = A sin t + B cos2t + Ct2 + D, where t is time. The dimension of ABCD is-