Question

Please share observations of physics practical :

1) To Study The Relation between force of limiting friction and normal reaction and to find the coefficient of friction between surface of moving block and that of horizontal surface

2) Determine young's modulus of the material of a given wire by using searle's apparatus.

Please share its urgent!!

Answer 1

Answer:

2. Answer- To Determine Young’s Modulus Of Elasticity Of The Material Of A Given Wire

Searle’s apparatus is used for the measurement of Young’s modulus. It consists of two equal length wires that are attached to a rigid support. To understand how Searle’s apparatus is used to determine Young’s modulus of elasticity of the material of a given wire, read below experiment.

Aim

To determine Young’s modulus of elasticity of the material of a given wire.

Materials Required

Searle’s apparatus

Two long steel wires of same length and diameter

A metre scale

A screw gauge

Eight 0.5kg slotted weights

1kg hanger

Theory

The normal stress for a wire with length L and radius r is loaded with weight Mg where l is the increase in length, then normal stress is given as:

Normal stress = Mgπr2

Longitudinal strain = lL

Hence, Young’s modulus = normalstresslongitudinalstrain Y=Mgπr2lL Y=MgLπr2l

Y can be calculated as the values of L and r are known and l is found by known Mg value.

Observations

Length of experimental wire AB, L = …..cm = ……m

Measurement of diameter of the wire

Pitch of the screw gauge (p) = 0.1cm

No.of divisions on the circular scale = 100

Least count of screw gauge (L.C) = 0.1/100 = 0.001cm

Zero error of screw gauge (e) = …….cm

Zero error of screw gauge (e) = -e = ……cm

Answer 2

Answer:

the friction is a force that always opposes motion between two surfaces in contact with each other and depends on the nature of the surface in contact.

the maximum value of frictional force between the two surface is known as limiting friction. In other words we can say that limiting friction is a maximum force of static friction which just allows a birthday to slide over another. It should be noted that in this limiting situation of friction the object does not actually more for slide it only just tends to move. The limiting friction depends upon the nature of the surfaces in contact. When the applied force exceed the limiting friction the wooden block start moving or sliding when an object moves in the presence of friction effective force acting on it is the difference between the applied force and the force of limiting friction