Question Details

The frequency of vibration f of a mass m suspended from a spring of spring constant k is given by a relation f = amˣkʸ, where a is a dimensionless constant. The values of x and y are

Options

A

x = 1/2 , y =1/2

B

x = -1/2 , y = -1/2

C

x = 1/2 , y = -1/2

D

x = -1/2 , y =1/2

Correct Answer :

x = -1/2 , y = 1/2

Solution :

The correct option is x = -1/2 , y = 1/2.

To find the values of x and y, we can use the method of dimensional analysis.

The given relation is:
f=amxky

Let us write down the dimensions of each quantity involved in the relation:
1. Frequency (f) is the number of oscillations per unit time, so its dimension is:
[f]=[T-1]=[M0L0T-1]
2. Mass (m) has the dimension:
[m]=[M]=[M1L0T0]
3. Spring constant (k) is defined as force per unit length (k=Fd). The dimension of force is [MLT-2] and length is [L]. Thus, the dimension of k is:
[k]=[MLT-2][L]=[MT-2]=[M1L0T-2]
4. The constant a is dimensionless, so it does not affect the dimensional equation.

Substituting these dimensions into the given relation:
[M0L0T-1]=[M]x[MT-2]y
Simplifying the right-hand side:
[M0L0T-1]=[Mx+yT-2]

By equating the powers of corresponding quantities on both sides, we get:
For mass (M):
x+y=0 --- (Equation 1)
For time (T):
-2y=-1 --- (Equation 2)

From Equation 2, we find y:
y=12

Substituting the value of y in Equation 1:
x+12=0
x=-12

Thus, the values are x=-1/2 and y=1/2.

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