Definitely D. The brakes on a bike rub against the wheel. Not sure about the others.
answer:
yes
explanation:
At a separation of the surface of Earth (r=6400km) gravity wants pull the test mass closer and closer. ... So the work done by gravity is NEGATIVE. The gravitational potential energy is negative because us trying to do the opposite of what gravity wants needs positive energy.
Answer:
(a) B = 5.6 micro Tesla
Explanation:
Current in the wire, i = 140 A
distance, r = 5 m
The formula for the magnetic field at a distance r due to the current carrying wire


B = 5.6 x 10^-6 Tesla
B = 5.6 micro Tesla
(b) As the magnetic field of earth at this site is 20 micro tesla so the magnetic field due to current carrying wire interfere the magnetic compass.