B because I’ve done this before
Answer:
Dimensions of the original rectangle:
Length = 19 cm
Width = 11 cm
Step-by-step explanation:
Let
Length = x
Width = y
Original rectangle:
2(Length + width) = 60
2x + 2y = 60
New rectangle has same length with original rectangle but half of the width of the original rectangle when folded
Length = x
Width = 1/2y
2(Length + 1/2width) = 49
2x + y = 49
2x + 2y = 60 (1)
2x + y = 49 (2)
Subtract (2) from (1) to eliminate x
2y - y = 60 - 49
y = 11
Substitute y = 11 into (2)
2x + y = 49
2x + 11 = 49
2x = 49 - 11
2x = 38
x = 38/2
x = 19
Dimensions of the original rectangle:
Length = 19 cm
Width = 11 cm
For this case we have the following equation:

Where,
w: The weight of a spring in pounds
E: the energy stored by the spring in joules.
Substituting values we have:

Making the corresponding calculation:
Answer:
the approximate weight of the spring in pounds is: