Heat and Energy — PHYSICS STD 9 — Question

The table below shows the distance travelled by two vehicles A and B during each second :

Time (s)	0	1	2	3	4	5	6	7
Distance travelled by A (m)	0	20	80	180	240	300	360	420
Distance travelled by B (m)	0	10	40	90	160	250	360	490

Which vehicle is moving with a constant acceleration?

State two characteristics which a source of energy must have.

Name the mirror which always produces an erect image of the objects.

How does the air inside the greenhouse remain warm?

State the effect of pressure on the speed of sound in air.

What is a leap year?

A person in front of a spherical mirror finds his image having a very small head, a fat body and legs of normal size. What are the shapes of three parts of the mirror?

What do you mean by the term neutral point?

Does sound require a material medium for transmission?

Is the following statement correct? If not, modify it suitably to make it correct. "The earth moves round the sun with uniform velocity".