In the figure, two identical ideal massless springs have unstretched lengths of 0.25 m and spring constants of 700 N/m. The springs are attached to a small cube and stretched to a length L of 0.30 m as in Figure A. An external force P pulls the cube a distance D = 0.020 m to the right and holds it there. (See Figure B.) The external force P, that holds the cube in place in Figure B, is closest to
A) 28 N.
B) 25 N.
C) 21 N.
D) 18 N.
E) 14 N.

Question

In the figure, two identical ideal massless springs have unstretched lengths of 0.25 m and spring constants of 700 N/m. The springs are attached to a small cube and stretched to a length L of 0.30 m as in Figure A. An external force P pulls the cube a distance D = 0.020 m to the right and holds it there. (See Figure B.) The external force P, that holds the cube in place in Figure B, is closest to 
A) 28 N. 
B) 25 N. 
C) 21 N. 
D) 18 N. 
E) 14 N.

Quizplus · Accepted Answer

The Answer of In the figure, two identical ideal massless springs have unstretched lengths of 0.25 m and spring constants of 700 N/m. The springs are attached to a small cube and stretched to a length L of 0.30 m as in Figure A. An external force P pulls the cube a distance D = 0.020 m to the right and holds it there. (See Figure B.) The external force P, that holds the cube in place in Figure B, is closest to 
A) 28 N. 
B) 25 N. 
C) 21 N. 
D) 18 N. 
E) 14 N.

In the Figure, Two Identical Ideal Massless Springs Have Unstretched