Final answer:
Calculating the number of balloons needed to float involves measuring the balloon's volume and weight, calculating the buoyant force, and comparing it to the total weight that needs to be lifted, followed by dividing the total weight by the lifting capacity of one balloon.
Step-by-step explanation:
To calculate the number of balloons needed to float, your friend needs to perform a series of calculations involving buoyancy, which is related to the balloons' volume and the density of the gas inside them, typically helium or hydrogen, which are lighter than air. First, she should find out the lifting capacity of one balloon, which depends on the volume of the balloon and the difference between the density of air and the density of the gas inside the balloon. Once the lift per balloon is determined, she can calculate the total weight that needs to be lifted and divide that by the lift provided by one balloon to find out how many balloons are required.
To perform these calculations, your friend might need to: measure the volume of the balloon using water or air displacement or a known formula based on the balloon's shape; weigh the balloon to find its mass; use the buoyant force equation (buoyant force = volume x (density of air - density of the lifting gas)) to calculate the lifting force of one balloon; and divide the total weight to be lifted by the buoyant force of one balloon to determine the total number of balloons needed.
The key steps in this process are:
- Measure the volume of a balloon (using displacement or mathematical techniques).
- Calculate the mass of the balloon.
- Use the mass and volume to determine the buoyant force exerted by the air on the balloon.
- Subtract the mass of the balloon from the buoyant force to get the net lift.
- Divide the total weight of the object to be lifted by the net lift per balloon.
Tools appropriate for taking these various measurements include:
- A scale for measuring weight (e.g., mass of the rubber in the balloon).
- A graduated cylinder or large container with volume markings for the water displacement method.
- A tape measure for dimensions if using a formula for volume.