Physics Chapter 2 Problems

 

Example No. 2.1:

Radius of a sphere = 0.20cm

p=3.142

Find the surface area of the sphere and express the answer in significant figure.

SOLUTION:

Given Data:

Radius

 r=           0.20cm

p=           3.142

Required Data:

Surface area       A=?

Formula:              A=4pr²

A= 3× 3.142 x (0.20)²

A= 4x 3.142x0.04

A = 0.50272 cm²

Therefore answer should be given up to two significant figures. Thus the surface area is

Ans:       A=0.5cm²

Example No. 2.2:

Find the volume of a rectangular box whose dimensions are given below:

Length of a box                                 =2.00cm

Breadth of the box          =1.5cm

Height of the box             =1cm

SOLUTION:

Given Data:

I=2.00cm

b=15cm

h=1 cm

Required Data:

v=?

Formula:

V=lbh

V=2 x 1.5 x 1

V = 3.00 cm³

Thus the answer should be given in only one significant figure is

Ans. V = 3 cm³

Example No. 2.3:

A steel rod has a diameter of 2.52 cm. Express its diameter in

1.      Millimeters

2.     Meter

SOLUTION:

Given Data:

Diameter of steel rod

D=2.52cm

Required Data:

Diameter in mm =?

Diameter in m=?

Formula:

Millimeters:

Diameter in mm from cm

D=2.52 x10

Therefore:   1 cm = 10mm

It has three significant figure.

 Ans.

Meter:

Diameter in m from cm

D=2.52 x 1/100 

D=2.52x 1/100 m

                        D=25.2mm

Ans. it has also three significant figure.