Motion and Meas...

How do we decide whether an object is in motion or at rest? 

Which among the following is in motion?

Which of the following are the greatest inventions of all time?

Boat is a means of 

In the beginning of the $$19^{th}$$, the invention of _________ introduced a new source of power.

Rohan was asked to measure the length and breadth of the box by his teacher. He used a metre scale for measurement and placed the scale as shown in the diagram. Which is this the correct way of measuring the box?

Pooja had to find the area of a box. So to find the length and breadth she used a metre scale.But the scale she had was broken at the ends and the zero mark could not be seen. When she placed the metre scale, one end had 2 cm reading and the other end had 10.8 cm. 
What is the length measured?

In ancient times, the means of transport used were

Which of the following are used as a mode of transport on water?

Which of the following are used as a mode of transport on air?