My answer is "Watt per square meter".
Complete Question
The complete question is shown on the first uploaded image
Answer:
The work done by the spring is = 
Explanation:
Force = torque × length
Given
F = 9.13 N
length (L) = 5.91 cm = 0.0591 m [Note 1 m = 100 cm ]
considering the formula above
where k denotes torque
Energy Stored 
Answer:
<h2>
14.66secs</h2>
Explanation:
Given the formula for calculating the depth in metres expressed as
depth in meters = ½ (1500 m/sec × Echo travel time in seconds)
Given depth of the challenger = 10, 994 meters, we will substitute this given value into the formula given to calculate the time take for the echo to travel.
10, 994 = depth in meters = ½ * 1500 m/sec × Echo travel time in seconds
10,994 = 750 * Echo travel time in seconds
Dividing both sides by 750;
Echo travel time in seconds = 10,994 /750
Echo travel time in seconds ≈ 14.66secs (to two decimal places)
Therefore, it would take an echo sounder’s ping 14.66secs to make the trip from a ship to the Challenger Deep and back
