Question Details

In two systems of relations among velocity, acceleration and force are respectively v₂ = (α²/ß)v₁, a₂ = αßa₁ anf F₂ = F₁/αß .If α and ß are constants then relations among mass, length and time in two systems are

Options

A

M₂ = αM₁/ß, L₂ = α²L₁/ß², T₂ = α³T₁/ß

B

M₂ = M₁/α²ß², L₂ = α³L₁/ß³, T₂ = T₁α/ß²

C

M₂ = α³M₁/ß³, L₂ = α²L₁/ß², T₂ = αT₁/ß

D

M₂ = α²M₁/ß², L₂ = αL₁/ß², T₂ = α³T₁/ß³

Correct Answer :

M₂ = M₁/α²ß², L₂ = α³L₁/ß³, T₂ = T₁α/ß²

Solution :

To find the relations among mass, length, and time in the two systems, we start by expressing velocity (v), acceleration (a), and force (F) in terms of their fundamental dimensions: mass (M), length (L), and time (T).

The dimensional formulas for these quantities are:
Velocity: [v]=LT-1
Acceleration: [a]=LT-2
Force: [F]=MLT-2

Let the units in System 1 be M1, L1, T1 and in System 2 be M2, L2, T2.
We are given the following relations between the two systems:
1) v2=α2βv1
2) a2=αβa1
3) F2=F1αβ

First, we find the relation for time (T). We know that acceleration divided by velocity gives a quantity with dimensions of T-1:
av=LT-2LT-1=T-1=1T
Therefore, we can write:
a2v2=1T2 and a1v1=1T1

Substitute the given relations of velocity and acceleration:
1T2=a2v2=αβa1α2βv1=αβα2βa1v1=β2α1T1
Taking the reciprocal of both sides, we get:
T2=αβ2T1=T1αβ2

Next, we find the relation for length (L). We know that velocity squared divided by acceleration has dimensions of length:
v2a=L2T-2LT-2=L
Therefore, we can write:
L2=v22a2=α2βv12αβa1=α4β2v12αβa1=α3β3v12a1=α3β3L1
Thus, the relation for length is:
L2=α3L1β3

Finally, we find the relation for mass (M). We use the relation for force, where F=Ma (Mass × Acceleration):
M=Fa
Therefore, we can write:
M2=F2a2=F1αβαβa1=1α2β2F1a1=1α2β2M1
Thus, the relation for mass is:
M2=M1α2β2

Combining these three results, the relations among mass, length, and time in the two systems are:
M2=M1α2β2, L2=α3L1β3, T2=T1αβ2

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