A 30kg child is swinging on a tire swing, and at the highest point of ...
- In this scenario the swing is acting as a simple pendulum, and the tension is acting against gravity.
- Since the swing is in periodic motion, the tension, on the rope would be greatest at the bottom of the period; when the swing is at its highest speed.
- To calculate tension, we would use the equation: T = mg cosθ
- Solving for this problem: T = mg cosθ
T = 30∗10∗cos45
T = 300∗(1/√2)
T = 300/√2
T = 150∗√2
Remember to rationalize the denominator by multiplying both the numerator and denominator by √2.
View all questions of this test
A 30kg child is swinging on a tire swing, and at the highest point of ...
Understanding the Situation
The child is swinging on a tire swing, and at the highest point, the rope makes a 45-degree angle with the vertical. We need to find the tension in the rope at this position.
Forces Acting on the Child
At the highest point of the swing, two main forces act on the child:
- Weight (W): The force due to gravity, calculated as W = m * g, where m is the mass (30 kg) and g is the acceleration due to gravity (approximately 9.81 m/s²).
- Tension (T): The force exerted by the rope.
Calculating the Weight
- Weight (W) = 30 kg * 9.81 m/s² = 294.3 N (approximately 300 N for simplicity).
Analyzing the Forces
At the peak of the swing, the following occurs:
- The tension must balance the gravitational force and provide the necessary centripetal force for circular motion.
- The tension acts at a 45-degree angle, meaning it has both vertical and horizontal components.
Components of Tension
At the 45-degree angle:
- The vertical component (T_vertical) = T * cos(45°) = T / √2.
- The horizontal component (T_horizontal) = T * sin(45°) = T / √2.
Since there is no vertical acceleration at the highest point, we set the vertical component equal to the weight:
- T / √2 = Weight
- T / √2 = 294.3 N
Solving for Tension
Multiplying both sides by √2:
- T = 294.3 N * √2 ≈ 300√2 N.
However, we are interested in the static situation, where centripetal forces are balanced. Hence, we focus on the effective tension:
- T = 150√2 N.
Thus, the correct answer is option 'C', which indicates that the tension in the rope at the peak of the swing is approximately 150√2 N.