Answer:
Current = 8696 A
Fraction of power lost = = 0.151
Explanation:
Electric power is given by
where I is the current and V is the voltage.
Using values from the question,
The power loss is given by
where R is the resistance of the wire. From the question, the wire has a resistance of per km. Since resistance is proportional to length, the resistance of the wire is
Hence,
The fraction lost =
Answer:
(a)
(b)
(c)
Explanation:
(a) According to Newton's second law, the acceleration of a body is directly proportional to the force exerted on it and inversely proportional to it's mass.
(b) According to Newton's third law, the force that the sled exerts on the girl is equal in magnitude but opposite in the direction of the force that the girl exerts on the sled:
(c) Using the kinematics equation:
For the girl, we have and
. So:
For the sled, we have . So:
When they meet, the final positions are the same. So, equaling (1) and (2) and solving for t:
Now, we solve (1) for