# Hi!

I have a physics test and need help with a few study questions...if you know which equations to use or how to solve any of these PLEASE tell me...thankyou!

1. One cubic meter of liquid air at standard temperature and pressure is about 900 kg. When this much liquid air turns to gaseous air of density 1.25 kg/m to power (3), what will its volume be?

2. How much lift will be exerted on airplane wings of 100 m to power of (2) area when the difference in air pressure below and above is 3 percent of atmospheric pressure?

3. What is the volume of a 50 kg person who can just barely float in fresh water?

4. A rectangular barge, 5.0 m long and 2.0 m wide, floats in fresh water. How much deeper will it float when its load is a 600 kg horse?

5. A 10 kg piece of wood that is 0.8 times the density of water floats in water. What mass of water is displaced?

6. Consider and object with a length at rest of 6 meters. When it approaches the speed of light, an observer at rest would measure its length approaching what value?

7. How fast must a particle move if its momentum is to be 3.3 times its classical momentum?

8. The fractional change of mass to energy in a fission reactor is about 0.1%, or 1 part in a thousand. If 1.0 kg of uranium undergoes fission, what amount of energy is released?

I know there's quite a few, but if anyone could help I would really appreciate it!

Volume = (Mass)/(Density)

## Sure! I'd be happy to help you with your physics questions. Let's go through each question and identify the relevant equations or concepts needed to solve them.

1. To find the volume of the gaseous air, you can use the equation:

Volume = (Mass) / (Density)

In this case, the mass is given as 900 kg, and the density of gaseous air is 1.25 kg/m^3.

Substituting these values into the equation, you can calculate the volume.

2. To determine the lift exerted on airplane wings, you need to use Bernoulli's principle. The relationship between pressure difference, velocity, and area can be given as:

Pressure difference = (Density) * (Gravity) * (Height difference)

Here, the pressure difference is given as 3 percent of atmospheric pressure, and the area is given as 100 m^2.

Using this information and the known values for density and gravity, you can solve for the height difference.

3. The volume of a person who can just barely float in fresh water can be calculated using Archimedes' principle. The principle states that the buoyant force acting on an object submerged in fluid is equal to the weight of the fluid displaced by the object. In this case, the person's weight is equal to the buoyant force. You can calculate the volume of water displaced, which will be equal to the person's volume.

4. To determine how much deeper the barge will float when a load is applied, you need to consider the principle of buoyancy. The buoyant force acting on the barge with and without the load will be different. You can calculate the difference in buoyant force and then use Archimedes' principle to determine the change in the depth to which the barge will float.

5. The mass of water displaced by the floating wood can be calculated using Archimedes' principle. The buoyant force acting on the wood is equal to the weight of the water displaced. By determining the volume of water displaced, you can find the mass of water.

6. When an object approaches the speed of light, its length appears contracted to an observer at rest. This phenomenon is described by the concept of length contraction. The equation used to calculate the contracted length is given by:

Contracted Length = (Rest Length) * (sqrt(1 - (v^2/c^2)))

Here, "v" is the velocity of the object and "c" is the speed of light. By substituting the appropriate values into the equation, you can find the contracted length.

7. According to the theory of relativity, the momentum of an object can be expressed as:

Momentum = (Mass) * (Velocity)

If the particle's momentum is to be 3.3 times its classical momentum, you can set up the equation and solve for the velocity.

8. The amount of energy released in a fission reaction can be calculated using Einstein's famous equation:

Energy = (Change in Mass) * (c^2)

In this case, the change in mass is given as a fractional change of 0.1% or 1 part in a thousand. By multiplying the change in mass with the speed of light squared, you can find the amount of energy released.

I hope this helps you tackle the questions on your physics test! If you have any further questions or need additional assistance, feel free to ask. Good luck!