The drag force F on a boat varies jointly with the wet surface area A of the boat and the square of the speed s of the boat. A b
1 answer:
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Answer:
Clockwise
Explanation:
According to Faraday-Newmann-Lenz's law, when there is a change in magnetic flux linkage through a coil, an emf is induced in the coil, and it is given by the equation
where
N is the number of turns in the coil
is the rate of change of magnetic flux in the coil
The negative sign in the formula indicates the direction of the induced emf, which is such that it opposes the direction of change in magnetic flux that originated the emf.
In this problem:
- At the beginning, the magnetic field is 1 T directed into the page
- Then, this magnetic field changes uniformly to 1 T directed out of the page (opposite direction)
We split the problem into two parts:
- In the first part, the strength of the magnetic field changes uniformly from 1 T to 0. This means that the magnetic flux through the coil is decreasing: therefore, the induced emf must be such that it produces a magnetic field that try to add to the original field. Using the right hand rule (thumb in the direction of the current in the loop and other fingers "wrapped" to give the direction of the field), we see that in order to produce a magnetic field into the page, the current must be clockwise.
- In the second part, the strength of the magnetic field changes uniformly from 0 T to 1 T, but in the direction out of the page. This means that the magnetic flux through the coil is increasing: therefore, the induced emf must be such that it produces a magnetic field that try to subtract to the original field, therefore the new produced field must be into the page (opposite direction to the external field).. Using the right hand rule again, we see that in order to produce a magnetic field into the page, the current must be clockwise again.
Answer:
1) Measuring cylinder
2) Top Pan Balance
Explanation:
To find the density of the pebble Nabil should first accurately measure the mass of the pebble using the top pan balance
He should then fill the displacement can till the water reaches the outlet pipe at the to of the cylinder
He should then place the pebble into the cylinder carefully ans allow the water that would start coming out to stop
The volume of water in the displaced cylinder is then measured and the density is found by dividing the mass of the pebble by the volume of water in the measuring cylinder
P=25x10^6 andF=750.So plug in everything to solve for A. which is 3x10^-5m^2 OR 0.3mm^2