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
You might also like to view...
Which of the following is the rate at which energy is transferred?
a. potential energy b. kinetic energy c. mechanical energy d. power
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).
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.
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