chapter 1 - basic physics tutorial

8/16/2019 Chapter 1 - Basic Physics Tutorial

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BASIC PHYSICS


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Example 1

- Write down the dimensions of

a) Acceleration? [LT-2

]b) Energy? [ML2T-2]

c) ower? [ML2T-!]

d) Moment"m? [MLT-#]

e) Electric $harge? [AT]


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Example 2

- The %o"ng&s mod"l"s E of a solid is gi'en by

where

E is the %o"ng(s mod"l"s mod"l"s of elasticity)

F is the force e*erted on an ob+ect "nder tension, A0 is the original cross-sectional area thro"gh which the force is alied,

ΔL is the amo"nt by which the length of the ob+ect changes,

L0 is the original length of the ob+ect.

/ind the dimensions of %o"ng&s mod"l"s.

Answer0[ML-#T-2]


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Example 3

- /or an ob+ect mo'ing with "niform acceleration1 the 'elocity ' is

gi'en by the e"ation '2 3 4 *1 where is constant and * is a

'ariable.

What are the dimensions of term *?

Answer0

[L2T-2]


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Example 4

- The e"ation for real gases may be e*ressed as follows0

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)6 7 b) 3 n8T where 3 ress"re1 6 3 'ol"me1 T 3 absol"tetemerat"re1 n3 n"mber of moles and 8 3 molar gas constant.

What are the dimensions of a and b?

Answer0

9imension of a is [ML:T-2] and b is [L!]


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Example 5

- The dimensions of the base "antities of length1 mass1 time1 amo"nt

of s"bstance and temerat"re are denoted by the symbols L1 M1 T1

; and < resecti'ely. What are the dimensions of 8 in the e"ation

6 3 n8T?

[9imensions of 0 ML-#T-21 60 L!1 n0;1 T0


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Example 6

- /ermi energy Ef is a concet in "ant"m mechanics. =t is the energy

of the highest occ"ied "ant"m state in a system of fermions at

>ero temerat"re. /ermi energy of a metal can be related to other

'ariables by Ef 3 hambnc 1 where is a constant of roortionality1 h

is a lanc constant1 m is the mass of an electron1 n is the n"mber

of free electrons er "nit 'ol"me. 9etermine by dimensional analysis

the 'al"es of a1 b and c .

[@nit for lanc constant h0 s]

Answer0

a = 2 1 b 3 -# and c = 2/3


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Example 7

- $hange the following "nit.

a) B2CC m h-2

3 DDDDD. m s-2

b) #2: cm! 3 DDDDD. m!

c) 2C g m s-2 3 DDDDD.g cm min-2

d) C. g cm-! 3 DDDDD.g m-!

e) 2C cm min-# 3 DDDDD.m s-#

Answer0

a) C.::F

b) #.2: * #C-G

c) B.2 * #CH

d) CCC

e) !.!! * #C-G


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Example 8

- The diameter of a shere is meas"red as F.2 cm. What is its

'ol"me in cm!1 m!1 mm!?

Answer

#C!B cm!1 #.C!B * #C-! m!1 #.C!B * #CF mm!

chapter 1 - basic physics tutorial

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