The acceleration a of an object is given by the equation a=A+Bt+Ct^3 where t refers to time. (a) What are the dimensions of A, B, and C? (b) What are the SI units for the constants A, B, and C?

Respuesta :

Answer:

(a) A = [tex][LT^{- 2}][/tex]

B = [tex][LT^{- 3}][/tex]

[tex]C = [LT^{- 5}][/tex]

(b) A = [tex]ms^{- 2}[/tex]

B = [tex]ms^{- 3}[/tex]

C = [tex]ms^{- 5}[/tex]

Solution:

The acceleration of a body is the rate at which the velocity of the body changes.

Thus

[tex]a = \frac{\Delta v_{o}}{\Delta t}[/tex]

The SI unit of velocity of an object is [tex]ms^{- 1}[/tex] and its dimension is [LT^{- 1}] and for time, T the SI unit is second, s and dimension is [T] and hence

The SI unit and dimension for the acceleration of an object is [tex]ms^{- 2}[/tex] and [LT^{- 2}] respectively.

Now, as per the question:

acceleration, a = [tex]A + Bt + Ct^{3}[/tex]

(a) Now, according to the homogeneity principle in dimension, the dimensions on both the sides of the eqn must be equal,

For the above eqn:

[tex]LT^{- 2} = A + Bt + Ct^{3}[/tex]

Thus the dimensions of :

A = [tex][LT^{- 2}][/tex]

BT =  [tex][LT^{- 2}][/tex]

Thus for B

B = [tex][LT^{- 3}][/tex]

[tex]CT^{3} = LT^{- 2}[/tex]

[tex]C = [LT^{- 5}][/tex]

(b) For the units of A, B and C, we will make use of their respective dimensional formula from part (a)

where

L corresponds to length in meter(m)

T corresponds to time in seconds(s)

Now, for:

A = [tex][LT^{- 2}] = ms^{- 2}[/tex]

B = [tex][LT^{- 3}] = ms^{- 3}[/tex]

C = [tex][LT^{- 5}] = ms^{- 5}[/tex]