Fluids — PHYSICS STD 9 — Question

A sphere of iron and another sphere of wood of the same radius are held under water. Compare the upthrust on the two spheres.
[Hint: Both have equal volume inside the water].

A coil of insulated copper wire is wound around a piece of soft iron and current is passed in the coil from a battery. What name is given to the device so obtained? Give one use of the device mentioned by you.

Define the term acceleration due to gravity. State its average value.

The sonic boom of an aircraft has a time period of 0.00005s. Calculate the frequency of sound produced.

State the positions of neutral points when a magnet is placed with its axis in the magnetic meridian and with its north pole (i) pointing towards the geographic north and (ii) pointing towards the geographic south.

A body at rest is made to fall from the top of a tower . Its displacement at different instants is given in the following table :

Time (in s)	0.1	0.2	0.3	0.4	0.5	0.6
Displacement (in m)	0.05	0.20	0.45	0.80	1.25	1.80

Draw a displacement - time graph and state whether the motion is uniform or non - uniform ?

Give two examples of uniform circular motion from your daily life.

Define the term potential difference?

A spring is compressed against a rigid wall. Draw a neat and labeled diagram showing the forces acting on the spring.

What can you say about the motion of a body if:
Its time-displacement graph is a straight line.