Ex 13.8, 3 - The diameter of a metallic ball is 4.2 cm - Ex 13.8

Ex 13.8, 3 - Chapter 13 Class 9 Surface Areas and Volumes - Part 2

Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class


Transcript

Ex 11.4,3 The diameter of a metallic ball is 4.2 cm. What is the mass of the ball, if the density of the metal is 8.9 g per cm3? To find mass, we have to find volume of sphere Radius of sphere = r = 𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟/2 = 4.2/2 = 2.1 cm Now, volume of the sphere = 4/3 πr3 = 4/3 × 22/7 × 2.1 × 2.1 × 2.1 cm3 = 38.808 cm3 Now, Density = 𝑀𝑎𝑠𝑠/𝑉𝑜𝑙𝑢𝑚𝑒 8.9 = 𝑀𝑎𝑠𝑠/38.808 𝑀𝑎𝑠𝑠/38.808 = 8.9 Mass = (38.808 × 8.9) g Mass = 345.3912 g. Mass = 345.39g (approx) Therefore, mass of metallic ball is is 345.39g (approx)

Ask a doubt
Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.