A cylindrical metal bar of diameter 14cm and length 2m is melted and moulded into spherical balls. In the process, 5% by volume of metal is lost and what remains makes balls of radius 3.5cm.

- calculate the volume of metal used to make the balls.
- find to the nearest whole number the number of balls made
- find the total surface area of the metal bar
- find the total surface area of the balls made