Initially, a 2.00-kg mass is whirling at the end of a string (in a circular path of radius 0.750 m) Figure 8-9 The string has been slowly winding around a vertical rod, and a few seconds later the length of the string has shortened to 0.250 m.

What is the instantaneous speed of the mass at the moment the string reaches a length of 0.250 m?
A) 3.9 m/s
B) 9.3 m/s
C) 15 m/s
D) 225 m/s
E) 75 m/s

Question

Initially, a 2.00-kg mass is whirling at the end of a string (in a circular path of radius 0.750 m) Figure 8-9 The string has been slowly winding around a vertical rod, and a few seconds later the length of the string has shortened to 0.250 m. 
 
 What is the instantaneous speed of the mass at the moment the string reaches a length of 0.250 m?
A) 3.9 m/s 
B) 9.3 m/s 
C) 15 m/s 
D) 225 m/s 
E) 75 m/s

Quizplus · Accepted Answer

The Answer of Initially, a 2.00-kg mass is whirling at the end of a string (in a circular path of radius 0.750 m) Figure 8-9 The string has been slowly winding around a vertical rod, and a few seconds later the length of the string has shortened to 0.250 m. 
 
 What is the instantaneous speed of the mass at the moment the string reaches a length of 0.250 m?
A) 3.9 m/s 
B) 9.3 m/s 
C) 15 m/s 
D) 225 m/s 
E) 75 m/s