Archimede's Principle
Define Archimede's Principle.
The buoyant force is equal to the weight of the volume of water displaced by an object.
Define Bernoulli's Law.
P+density*gh+.5*mv^2=constant
What physical characteristics distinguish a fluid from a solid?
Solids can hold a shape and do not flow. Fluids cannot do either of those things.
Define Newton's Law of Universal Gravitation.
F=GMm/R^2
Define Newton's 3 Laws.
1st: an object at rest remains at rest and an object in motion remains in motion at a constant velocity unless acted upon by an outside force.
2nd: F=ma
3rd: forces come in equal and opposite pairs.
Does Archimede's Principle hold true in a 'weightless' environment, such as on the space shuttle?
Explain how the density of air changes with altitude.
At a higher altitude, there's less air above the other altitudes, so there's less air pushing down.
Why does a dull hypodermic needle hurt more than a sharp one?
There is a smaller force being applied, but it was applied over a larger area.
What does the Universal Gravitational Constant, G, measure?
It measures the strength of gravity between two objects.
Define 'g'.
It's the acceleration due to gravity for an object. On Earth, it is 9.81 m/s^2
More force is required to pull a plug on a bathtub when it is full vs when it is empty. Why?
The weight of the water will be pushing down on the plug and you would have to fight the buoyant force from the water vs the air (when the tub is empty).
What is P_0 (in words and value)?
atmospheric pressure at the surface of the Earth. P_0=1.01x10^5 Pa
How is pressure related to the sharpness of a knife and its ability to cut?
How is your weight determined by using Newton's Law?
It's the ratio of the masses of yourself, the Earth, and the radius of the Earth.
Define the conservation of momentum and energy.
E_i=E_f and p_i=p_f
Will the same ship float higher in salt water than in freshwater? Explain your answer.
The buoyant force is equal to the weight of the fluid displaced. The greater the density of the fluid, the less fluid that is needed to be displaced to have the weight of the object be supported and to float. Since the density of salt water is higher than that of fresh water, less salt water will be displaced, and the ship will float higher.
What does the constant usually equal in Bernoulli's equation?
Why is mercury used in barometers rather than water?
Mercury stays liquid for a larger range of temperatures than water does. It is also much more dense.
If you were 5 times farther from the center of the Earth, what would your difference in weight be?
1/25
What are the components of a velocity equal to when doing a projectile motion problem?
v_x=v_0*cos(theta)
v_y=v_0*sin(theta)
If the weight of an object that is submerged in a fluid is 10 N and the buoyant force on it is 20 N, what will happen to the object?
Based on Bernoulli's Equation, what are the three types of energy in a fluid?
Kinetic, potential, and work done by a force.
Why is it difficult to swim underwater in the Great Salt Lake?
True or False: Above Earth's atmosphere, there is no gravity?
False.
Suppose someone wants to construct a loop for a rollercoaster. What ideas will they use to make sure the train makes it over the loop?
Circular motion, centripetal acceleration and force, friction.