Question

1. Name the two different kinds of friction and briefly describe them.         
2. The data below for the instantaneous velocity v versus the time t were obtained in a level 300 student experiment. Perform a linear least square fit with v as the vertical axis and t as the horizontal axis.

v(m/s)	0.352	0.496	0.655	0.808	0.939	1.073
t(s)	0.200	0.400	0.600	0.800	1.000	1.200

Table 1: v versus t

Determine from the graph;

2. 1. Acceleration a
   2. Initial velocity v_o - (Intercept)          
3. Mention the equipment used to measure the following quantities in the laboratory and state their corresponding SI unit of measurements;
   1. Voltage
   2. Current

Magnetic flux density           

Answer 1

Friction:-When the two bodies arre contact to each other there is a contact force in between them,which is resolved into two components such as,the perpendicular component is called as "normal force'.The parallel component is called as friction.

The frictions are two types such as

i)Kinetic friction

ii)Static friction

I)KInetic friction:-

When two so;id bobies slip over each other,the force of friction is called as kinetic friction.The directions of the frictional forces are such that the relative slipping is opposed by the friction.

Suppose a body A in contact with B is mved with respect to it as shown in figure(2).The force of friction acting on A due to B will be opposite to the velocity of A with respect to B.The force of friction acting on B due to A will be opposite to velocity of B with respect to A.

Magnitude of kinetic friction:-

The magnitude of kinetic friction is directly proportional to the normal force acting between the bodies.

Therefore, f_k=_kN

where _k=Co-effecient of kinetic friction

N=Normal force

ii)Static friction:-Frictional forces can also act between two bodies which are in contact but are not sliding with respect to each other.The friction in such cases is called as static friction.For example,suppose several labourers are trying to push a heavy almirah on the floor tp it out of the room.

Magnitude of static friction:-

The magnitude of static friction is directly propoorttionl to the nromal forc.

Therfore f_s=_sN    

Where   _s=Co-effecient of static friction

N=Normal force

From the above graph the trendline equation is y=0.726x+0.211 which is similar to the straight line equation as y=mx+c

Slope(m)=0.726 which represents the accelaration

Therefore accelaration (a)=0.726

The y-intercept V_o=0.211(initial velocity)

b)i)The voltage is measured by the voltmeter in the laboratory the same can be measured by multimeter.The units are (Volts).

ii)The current is measured by the ammeter in thr laboratory by milliammeter(mA) or microammeter(A) units are (amperes).

iii)The magnetic flux density is measured by using the Teslameter.Units are (Tesla).