Physics word problems regarding basic concepts

In summary, a sharp knife cuts better than a dull knife due to its finer edge and smaller surface area, which allows for more pressure to be exerted on the molecules. To begin solving the other problems, consider the differences between the given scenarios and what factors could affect the pressures, mass, volume, and density in each situation.
  • #1
jon.physics
2
0

Homework Statement


Explain why a sharp knife cuts better than a dull knife


Homework Equations


None that i know of


The Attempt at a Solution


Not sure where to begin

1. The problem statement, all variable and given/known data
what happens to the density of air in a common rubber balloon when it is heated

2. Homework Equations
none that i know of

3. The Attempt at a Solution
not sure where to begin

1. The problem statement, all variable and given/known data
How does water pressure 1 meter beneath the suface of a lake compare with water pressure 1 meter below the surface of a swimming pool

2. Homework Equations
none that i know of

3. The Attempt at a Solution
not sure where to begin

1. The problem statement, all variable and given/known data
when an air bubble rises in water, what happens to its mass, volume, and density

2. Homework Equations
not sure

3. the attempt at a solution
not sure

I'm sorry but my professor has not been present for the past couple of weeks so I'm confused as to where to begin. This is my first semester taking physics ever and I'm having a difficult time understanding these word problems. any help would be great. thanks
 
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  • #2
Pressure=force/area.

A sharp knife has a finer edge which can be read as having less surface area. The force of the cutting is dispersed among a smaller surface. Cutting with a dull knife might not generate enough pressure to tear the molecules apart.
 
  • #3
Thanks I appreciate that. Can anyone help me with the other questions?
 
  • #4
Since you didn't attempt anything yet, I'll only give you hints on where to begin.
2) What's the difference between the lake and a swimming pool? Is there a difference? What would make the pressures different? Is any difference? What kind of factors changes pressure?

3) Think about what happens if its mass changes. If it does change, why does it change? Where would it go? What affects a gas's volume? Surely if the air bubble were stationary (somehow just staying in the same place) its mass and volume would be the same. What changes does rising do, if any? What still stays the same? Density is related to mass and volume, so don't worry about density until you've figured out what happens to the mass and volume.
 

1. What is the definition of velocity in physics word problems?

Velocity is a measure of the rate and direction of an object's movement. It is typically represented by the symbol v and is calculated by dividing the change in an object's position over time. In physics word problems, velocity is often given in units of meters per second (m/s).

2. How is acceleration calculated in physics word problems?

Acceleration is the rate of change of an object's velocity. It is typically represented by the symbol a and is calculated by dividing the change in an object's velocity over time. In physics word problems, acceleration is often given in units of meters per second squared (m/s^2).

3. What is the difference between distance and displacement in physics word problems?

Distance is the total length traveled by an object, while displacement is the straight line distance between an object's starting and ending points. In physics word problems, distance is often given in units of meters (m) and displacement is given in units of meters (m) or kilometers (km).

4. How do you calculate force in physics word problems?

Force is a measure of the push or pull on an object. It is typically represented by the symbol F and is calculated by multiplying an object's mass by its acceleration. In physics word problems, force is often given in units of Newtons (N).

5. What is the formula for work in physics word problems?

Work is a measure of the energy transferred to or from an object by a force. It is typically represented by the symbol W and is calculated by multiplying an object's force by its displacement. In physics word problems, work is often given in units of Joules (J).

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