Question

A solid metallic rod 15cm long with diameter 3.5cm is melted and made into a rod of radius 3.5cm.What Will be the length of the rod?

Answer 1

Length of first rod = 15 cm
Radius of first rod = 3.5/2 cm
Volume of first rod = pi *r*r*h
= pi * 3.5 * 3.5 * 15 / 4 cm^3 --------


Radius of second rod = 3.5 cm
Volume of second rod = Volume of first rod
=> pi * 3.5 * 3.5* h = pi *3.5*3.5*15 / 4
=> h = 15/4

Length of second rod = 15/4
= 3.75 cm

Answer 2

ATQ
STEP BY STEP EXPLANATION
A solid metal rod
Length= 15cm
Diameter=3.5cm
Radius=D/2 =3.5/2=35/20=7/4=1.75cm
Volume of the first rid=πr²h
Radius of the second rod=3.5cm
Length of the rod-
Volume of the second rod=Volume of the first rod.
πr²h=πr²h
π*3.5*3.5*h=π*1.75*1.75*15
h=22*1.75*1.75*15*7/22*3.5*3.5
h=1.75*1.75*15/12.25
h=3.75cm
Therefore the length of the new rod = 3.75cm