In: Physics
A 82.0 kg worker climbs a cell tower which is 72.0 m tall. The worker brings 208 kg of tools and equipment to the top off the tower. The tower can be modeled as equivalent to a steel cylinder that has a cross sectional area of .022 m^2. By how much did the tower compress when the worker was at the top of the tower. Young's modulus for steel is 20.0 x 10^10 Pa.
A. .0465 mm
B. .0242 mm
C. .0345 mm
D. .0121 mm
Let the height of tower be represented as l and the height by which the tower is compressed is
Also,
and where = F is the force on the tower and A is the area of cross section of cylinder.
Also,
Here, Y = Young's modulus
So, putting the values of Stress and Strain, we get
Reorganising,
So,
Please refer to figure attached.
Here F is the net force on tower which is total mass of man and tool and gravity where is m is total mass of man and tool and g=9.8
Putting the values, we get
which is [Since so we multiply by to convert into mm ]
Hence, option A is correct.