To determine the man's speed at 60 cm above the ground, we can make use of the conservation of energy.
The potential energy of an object at a certain height is given by the formula:
PE = m * g * h
where: PE is the potential energy, m is the mass of the object, g is the acceleration due to gravity (approximately 9.8 m/s²), h is the height above the ground.
Since the speed of the man at 180 cm above the ground is zero, we can conclude that the potential energy at that point is maximum and equal to the potential energy at 60 cm above the ground. Therefore, we can set up the following equation:
m * g * h₁ = m * g * h₂
where: h₁ is the height at 180 cm above the ground, h₂ is the height at 60 cm above the ground.
Simplifying the equation:
h₁ = 180 cm = 1.8 m h₂ = 60 cm = 0.6 m
1.8 * g * m = 0.6 * g * m
The mass of the man cancels out, leaving us with:
1.8 * g = 0.6 * g
Simplifying further:
1.8 = 0.6
This equation is not valid, which means there must be some other forces acting on the man that affect his speed. In the given scenario, it seems that there are additional factors involved, such as the tension in the string or the presence of other forces (e.g., air resistance) that are not accounted for.