Question

1>Why is iron heavier than
wood for the same volume?
2> Define speed. Write its SI
unit.​

Answer 1

1. What is this mean is iron the space between iron molecules in iron much less than as that of wood. So in iron there is more molecules than wood in same volume. More molecules means more mass, that's why iron is much heavier than wood for same volume
2. Speed can be thought of as the rate at which an object covers distance. ... Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second, but the most common unit of speed in everyday usage is the kilometre per hour or, in the US and the UK, miles per hour.