Two students suggest different functions for the battery plays a flashlight.
Student A: "The battery supplies the charge which allows the light bulb to light. When the battery no longer works, it is because it has run out of charge."
Student B: "The battery pumps the charge around the circuit. The charge itself comes from the conducting elements of the circuit; the battery supplies the energy to pump this charge. When the battery no longer works, it is because the energy-producing chemicals have been consumed."
(a) Which student (A or B) do you agree with?

Student B is correct

Explanation:

The battery acts like a pump to drive the electric charge. The electric charge comes from the conducting material but the battery provides a potential difference or a gradient of flow for this charge which is necessary for the movement of the charge along the conductor.

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west