On entering the room of a child in Buck's traction, the nurse makes all of the following observations. Which observation requires a nursing intervention?

A) The child's traction weights are hanging freely.
B) The child is watching television quietly.
C) The foot of the bed is elevated on pillows.
D) The child reports mild discomfort in the affected leg.

In physics, tensions in cords are related to the weights they support in equilibrium. T1 is equal to the weight of the child and basket (55 N), and T2 is the sum of the child and basket's weight plus the scale's weight. The scale's mass is 0.500 kg, so its weight is 4.9 N and T2 totals to 59.9 N.

Explanation:

The student's question involves a scenario where a baby is being weighed and the nurse must observe tensions in cords as part of a physics problem relating to forces and equilibrium. When a scale reads 55 N for the mass of the child and basket, this means the combined weight is 55 N, since weight is the force exerted by gravity on an object. The mass can be calculated using the relationship Weight (W) = Mass (m) × Gravity (g), where g is approximately 9.8 m/s². To find the mass, we divide the weight by the acceleration due to gravity.

The tension T1 in the cord attaching the baby to the scale must be equal to the weight of the child and basket, which is 55 N, under the assumption that the system is in equilibrium and there are no other vertical forces acting on the system. Similarly, the tension T2 in the cord attaching the scale to the ceiling must be the sum of the weight of the child and basket and the weight of the scale itself. If the scale has a mass of 0.500 kg, its weight is 0.500 kg × 9.8 m/s² = 4.9 N. So the tension T2 would be 55 N + 4.9 N which equals 59.9 N.