A 10 kg box is suspended by two strings as shown above. The angle θ is 25 degrees. Assume the cord on the right is perfectly horizontal. The left-hand cord in the diagram above is 2 meters long. If the right-hand string is suddenly cut, determine the speed of the box as it passes through its equilibrium position. (number 1. b)
http://www.chs.d211.org/science/torpedw/AP%20Physics%20C/Unit%203-Energy/Conservation%20of%20Energy%20Problems.pdf

Question

A 10 kg box is suspended by two strings as shown above. The angle θ is 25 degrees. Assume the cord on the right is perfectly horizontal. The left-hand cord in the diagram above is 2 meters long. If the right-hand string is suddenly cut, determine the speed of the box as it passes through its equilibrium position. (number 1. b)
http://www.chs.d211.org/science/torpedw/AP%20Physics%20C/Unit%203-Energy/Conservation%20of%20Energy%20Problems.pdf

anonymous · Answer

|dw:1395291773526:dw|
to calculate velocity use energy conservation 
mgh= mv^2 /2 with h= 2-2sin25

anonymous · Answer

i got 4.79 m/s. what am i doing wrong?

anonymous · Answer

it should be h=2-2cos25 right?

anonymous · Answer

|dw:1395368988353:dw|
every thing is fine and i also got 4.79.