Answer:
1 joule = 0.737 foot-pound
Joule is the unit of work.
1 J = 1 N·m
In SI units
1 J = 1 kg· m/s²
0.737 foot-pound is the amount of work to raise 0.737 pounds one foot or raising one pound to 0.737 ft.
Answer:
A. Attractive
B. ( μ₀I² ) / ( 2πd )
Explanation:
A. We know that currents in the same direction attract, and currents in the opposite direction repel, according to ampere's law. In this case the current in the two wires are flowing in the same direction, and hence the force between the two wires are attractive.
B. Suppose that two wires of length
and
both carry the current
in the same direction ( given ). In the presence of a magnetic field produced by wire 1, a force of magnitude m say, is experienced by wire 2. The magnitude of the magnetic field produced by wire 1 at distance say d, from it's axis, should thus be the following -
= μ₀I / 2πd
The force experienced by wire 2 should thus be -
= I(
)
= I
Sin( 90 )
= I
( μ₀I / 2πd )
Therefore the force per unit length experienced by wire 2 toward wire 1 should be ...
(
/
) = ( μ₀I² ) / ( 2πd ) ... which is our solution
As per the question the distance of venus from sun is given as 0.723 AU
We have been asked to calculate the time period of the planet venus.
As per kepler's laws of planetary motion the square of time period of planet is directly proportional to the cube of semi major axis. mathematically

⇒
where is k is the proportionality constant
We may solve this problem by comparing with the time period of the earth . We know that time period of earth is 365.5 days
Hence
The distance of sun from earth is taken as 1 AU i.e the mean distance of earth from sun
Hence 
The distance of venus from sun is 0.723 AU i.e
From keplers law we know that-
⇒
Putting the values mentioned above we get-

⇒
⇒
Hence the time period of venus is 224.388352752710 days