A 2 kg ball is attached to a 0.80 m string and whirled in a horizontal circle at a constant speed of 6 m/s. The work done on the ball during each revolution is: * 1 point (A) 90 J (B) 72 J (D) 16 J (D) zero

The answer should be 36 Joules.

Explanation:

This can be solved as a angular motion.

Angular velocity w = V/r

Where V is the linear velocity 6 m/s

And r is the radius of rotation which is equal to the lenght of the string 0.8 m

w = V/r = 6/0.8 = 7.5 rad/s

Moment of inertia of rotation I = mr^2

Where m is the mass of the ball 2 kg

I = 2 x 0.8^2 = 1.28 kg-m2

From energy conservation, work done is equal to the kinetic energy of the angular motion.

KE = 0.5Iw^2

= 0.5 x 1.28 x 7.5^2 = 36 Joules.

nec chapter 5 contains

c. information on special occupancy areas

nec chapter 6 covers

a. special equipment

which of the following rules contain the words shall or shall not and must be adhered to?

b. mandatory rules

which of the following rules identify actions that are allowed but not required and typically cover options or alternative methods?

c. optional rules

which of the following serves as the introduction to the nec and provides an overview of the book?

a. nec article 90

organizations that test products for safety are

c. nrtls

the nec is published by the

a national fire protection association

the nec is divided into

b. 9 chapters

the nec provides informative annexes for

c. informational materials and examples

two terms from nec article 100 that trainees should become familiar with are

b. labeled and listed

explanation:

false br