A girl 36 kg occupies a seat of a swing that this subject by two chains 20 m in length each. If someone drops the girl from an 8 m position below the highest of the swing. What strength exercises it on the girl when she passes through the point lower?
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To find the strength exerted on the girl when she passes through the lower point of the swing, we need to consider the forces acting on her.
First, let's calculate the total length of the swing using the two chains. Since each chain is 20 m in length, the total length of the swing would be twice that, which is 40 m.
Next, let's calculate the height from which the girl drops. Given that the girl is dropped from a position 8 m below the highest point of the swing, we can calculate the height from the lowest point as follows:
Height from the lowest point = Total length of the swing - Height from the highest point
= 40 m - 8 m
= 32 m
Now, we can calculate the potential energy lost by the girl as she drops to the lowest point of the swing. The potential energy lost is given by the formula:
Potential Energy = mass * gravitational acceleration * height
Given that the weight of the girl is 36 kg (mass) and the gravitational acceleration is approximately 9.8 m/s^2, we can calculate the potential energy lost:
Potential Energy = 36 kg * 9.8 m/s^2 * 32 m
≈ 11,251.2 Joules
Finally, to find the strength exerted on the girl when she passes through the lower point of the swing, we need to consider the conservation of energy. At the highest point of the swing, all the potential energy is converted to kinetic energy. As the girl reaches the lowest point, all the potential energy is transformed back into kinetic energy.
Since no energy is lost due to friction or other forces, the strength exerted on the girl at the lowest point is the same as her weight. Therefore, the strength exerted on her is approximately 36 kg multiplied by the acceleration due to gravity, which is 9.8 m/s^2:
Strength exerted = 36 kg * 9.8 m/s^2
≈ 352.8 Newtons
So, when passing through the lowest point, the girl experiences a force of approximately 352.8 Newtons.