Answer:
a) Resistivity=R.A/L
Here, R=500000ohm, L=1.6m, A=2pi* (0.14/2)*0.002 m2=0.00088.........we have converted quantities into SI units
Resistivity=R.A/L
=500000*0.00088/1.6 = 440/1.6= 275 ohm.meter
b) pskin/pinterior =275/4.8=57.3
For second part, correct option is (A), because cross section area is smaller.
Answer:
Explanation:
The net force exerted on the mass is the sum of tension force and the external force of gravity.
is the tension force.
is the force of gravity.
where 
is the rope's radius from the fixed point.
From the net force equation above:
Hence the tension force is 6.046N
Answer: vl = 2.75 m/s vt = 1.5 m/s
Explanation:
If we assume that no external forces act during the collision, total momentum must be conserved.
If both cars are identical and also the drivers have the same mass, we can write the following:
m (vi1 + vi2) = m (vf1 + vf2) (1)
The sum of the initial speeds must be equal to the sum of the final ones.
If we are told that kinetic energy must be conserved also, simplifying, we can write:
vi1² + vi2² = vf1² + vf2² (2)
The only condition that satisfies (1) and (2) simultaneously is the one in which both masses exchange speeds, so we can write:
vf1 = vi2 and vf2 = vi1
If we call v1 to the speed of the leading car, and v2 to the trailing one, we can finally put the following:
vf1 = 2.75 m/s vf2 = 1.5 m/s
