Answer:
D) wood rubbed against a rough surface feels hot
Explanation:
The heat is transferred from one form of energy (friction of the wood being rubbed against the surface) to another (heat energy).
Answer:
The potential difference is 121.069 V
Solution:
As per the question:
Diameter of the cylinder, d = 9.0 cm = 0.09 m
Length of the cylinder, l = 40 cm = 1.4 m
Average Resistivity, 
Current, I = 100 mA = 0.1 A
Now,
To calculate the potential difference between the hands:
Cross- sectional Area of the Cylinder, A = 
Resistivity is given by:



Now, using Ohm's Law:
V = IR

Answer:
Final velocity v=19.83 m/sec
Explanation:
We have given initial velocity u =5.13 m/sexc
Acceleration of automobile 
Time t =4.9 sec
We have to find the final velocity v
According to first law of motion v = u+at ,here v is the final velocity , a is acceleration and t is time
So 
So the final velocity is 19.83 m/sec
1.
Answer:
Part a)

Part b)

Explanation:
Part a)
Length of the rod is 1.60 m
diameter = 0.550 cm
now if the current in the ammeter is given as

V = 17.0 volts
now we will have


R = 0.91 ohm
now we know that



Part b)
Now at higher temperature we have


R = 0.98 ohm
now we know that



so we will have



2.
Answer:
Part a)

Part b)

Explanation:
Part a)
As we know that current density is defined as

now we have

Now we have


so we will have

Part b)
now we have

so we have


so we have

