🏫 Board🧲 Physics

The displacement of a particle as a function of time is given by:\(x(t)=A\sin ⁡(t)+B{\cos ⁡}^{2}(t)+C{t}^{2}+D\). Find t…

Q1 FREE PREVIEW

The displacement of a particle as a function of time is given by:\(x(t)=A\sin ⁡(t)+B{\cos ⁡}^{2}(t)+C{t}^{2}+D\).

Find the dimension of \(\frac{ABC}{D}\)

(Shift I Memory Based)

a

\(\left[{\mathrm{L}}^{2}\right]\)

b

\(\left[{\mathrm{L}}^{2}{\mathrm{T}}^{−2}\right]\)

c

\(\left[{\mathrm{LT}}^{−2}\right]\)

d

\(\left[{\mathrm{L}}^{3}\mathrm{T}\right]\)

✓ Correct answer: b)

\(\left[{\mathrm{L}}^{2}{\mathrm{T}}^{−2}\right]\)

Explanation

The displacement \(x(t)\) has the dimension \([L]\). Each term in the equation must also have the same dimension \([L]\):

  • \(A\sin ⁡(t)\): \(\sin ⁡(t)\) is dimensionless, so \(A\) has \([L]\).
  • \(B{\cos ⁡}^{2}(t)\): \({\cos ⁡}^{2}(t)\) is dimensionless, so \(B\) has \([L]\).
  • \(C{t}^{2}\): \({t}^{2}\) has dimensions \([{T}^{2}]\), so \(C\) must have \([L{T}^{−2}]\).
  • \(D\): As part of the displacement, \(D\) has \([L]\).

Thus, the dimensions of \(\frac{ABC}{D}\)​ are:

\(\frac{[L]⋅[L]⋅[L{T}^{−2}]}{[L]}=[{L}^{2}{T}^{−2}]\)

Therefore, the correct answer is \((b)\).

Practice more Board Physics PYQs

See every question on Units and Measurements, or browse the full Board question bank.

See all questions on Units and Measurements →