Question

Difficulty: MediumDirect and Inverse Proportionality

A group of students conducted a physics experiment to study the relationship between the mass of a glider and its acceleration on a horizontal air track. A constant net force was applied to the glider during all trials. The students observed that the acceleration of the glider, aa, is inversely proportional to its mass, mm. During Trial 1, a glider with a mass of 0.20 kg0.20\text{ kg} was measured to have an acceleration of 5.0 m/s25.0\text{ m/s}^2. During Trial 2, a different glider was used under the same constant net force. If the mass of the glider in Trial 2 is 0.50 kg0.50\text{ kg}, what is the acceleration of the glider, in m/s2\text{m/s}^2?

Answer: 2 m/s^2

Answer

The acceleration of the glider in Trial 2 is 2.0 m/s^2.
Since acceleration is inversely proportional to mass, their product remains constant under a constant net force. Using the data from Trial 1, the constant is calculated as 0.20 kg×5.0 m/s2=1.0 N0.20\text{ kg} \times 5.0\text{ m/s}^2 = 1.0\text{ N}. In Trial 2, with a mass of 0.50 kg0.50\text{ kg}, the acceleration is found by dividing the constant by the new mass: 1.0/0.50=2.0 m/s21.0 / 0.50 = 2.0\text{ m/s}^2.

Step-by-Step Solution

1
Set up the inverse proportionality equation.
a×m=ka \times m = k
Since acceleration is inversely proportional to mass, their product must equal a constant value.
2
Calculate the constant of proportionality using Trial 1 data.
k=1.0k = 1.0
Substitute m=0.20 kgm = 0.20\text{ kg} and a=5.0 m/s2a = 5.0\text{ m/s}^2 into the equation: 5.0×0.20=1.05.0 \times 0.20 = 1.0.
3
Calculate the new acceleration for Trial 2.
a2=2.0 m/s2a_2 = 2.0\text{ m/s}^2
Substitute the constant k=1.0k = 1.0 and the new mass m2=0.50 kgm_2 = 0.50\text{ kg} into the equation: a2×0.50=1.0a_2 \times 0.50 = 1.0, so a2=2.0a_2 = 2.0.

Key Concept

Inverse proportionality relates two variables such that their product is constant. If one variable increases by a factor, the other must decrease by the same factor.
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