A 1.2-kg mass is projected down a rough circular track (radius = 2.0 m) as shown. The speed of the mass at point A is 3.2 m/s, and at point B, it is 6.0 m/s. What is the change in mechanical energy done on the system between A and B by the force of friction?
a.
?8.9 J
b.
?7.3 J
c.
?8.1 J
d.
?6.6 J
e.
?24 J
c
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Components: If a vector 
has components Ax < 0, and Ay > 0, then the angle that this vector makes with the positive x-axis must be in the range
A. 0° to 90°. B. 90° to 180°. C. 180° to 270°. D. 270° to 360°. E. It cannot be determined without additional information.
Which of the following is the rate at which energy is transferred?
a. potential energy b. kinetic energy c. mechanical energy d. power
How much power is theoretically available from a mass flow of 1000 kg/s of water when it falls a vertical distance of 100 meters?
A. 980 kW B. 98 kW C. 4900 W D. 980 W E. 9600 W
A series circuit consists of a 100 V DC power source, a 100 ? resistor, and a variable resistor of resistance R, which varies from 0 to 100 ?. The current in the circuit is
a.
directly proportional to R.
b.
inversely proportional to R.
c.
directly proportional to (100 ? + R).
d.
inversely proportional to (100 ? + R).
e.
neither directly nor inversely proportional to R or to (100 ? + R).