Physics Flashcards
What is the formula for speed?
S= D/T (speed = distance divided by time)
What is the formula for velocity?
V= D/T (velocity = distance divided by time + direction)
What is acceleration?
A change in the velocity of an object
What is the formula for acceleration?
Delta V/Delta T (change in velocity over change in time)
What are the SI units for velocity?
m/s (meters per second)
What are the SI units for acceleration?
m/s2 (meters per second squared)
How do we determine the change (delta) of time and velocity for acceleration?
Vfinal-Vinitial over Tfinal-Tinitial
What is Newton’s 1st Law?
The Law of Inertia: An object in motion tends to stay in motion, and an object at rest tends to stay at rest
What is required to overcome the inertia of an object?
an outside force
What is Newton’s 2nd Law?
The force/mass/acceleration relationship: the acceleration of an object is directly related to the force applied to an object and inversely related to the mass of the object
You’re pulling a wagon. Suddenly, the mass of the wagon is 5 times greater. The force you’re applying to the wagon is unchanged. What happens to the acceleration of the wagon?
It will decelerate (slow down)
What is Newton’s 3rd Law?
For every action (or force), there is an equal and opposite reaction (or reactive force).
If every force has an equal reactive force, how does anything move?
Because of the relationship WITHIN systems. We don’t calculate the force and opposing force at the same time; we only look at the forces that affect one object at a time.
What is the opposite force to gravity called?
the normal force
What is the difference between potential and kinetic energy?
potential energy is the possible energy of an object, kinetic energy is the energy of motion
What is the formula for kinetic energy?
Ke=1/2mv2 (Kinetic energy = 1/2 of object’s mass times velocity squared)
What is work?
Force x Distance (measured in Joules)
What is power?
Work/Time (work divided by time, measured in watts or horsepower)
What is friction?
Friction is the force that the surfaces of two objects exert on each OR the force that an environment exerts on an object’s surface
What is gravity?
the universal attractive force between objects
What direction does friction always move in the presence of motion?
In the opposite direction of the motion
What is static friction?
the friction present in objects that aren’t moving
Water and air moving against the surface of an object is an example of _________ friction.
fluid friction
Circular objects have rolling friction, which requires less force to overcome. Why is that the case?
reduced surface area contact between the objects
Why do we measure both weight and force in Newtons?
Because weight is the product of mass and the force that gravity exerted on that mass (1 kg x 9.8 m/s2 = 9.8 N of weight)
What is terminal velocity?
The final velocity of a falling object when it can no longer accelerate.
What is elastic potential?
the ability of a material to compress or stretch under force and return to its original shape
What is the formula for elastic potential?
W=Fs (Elastic potential = Force x Distance of Displacement)
What is the restorative force?
The force exerted by a stretched or compressed material as it returns to its original state
What’s the Zeroth Law of Thermodynamics?
If two systems are in equilibrium with a third system, then the first two are in equilibrium with each other.
What’s the 1st Law of Thermodynamics?
Energy, including heat energy, cannot be created or destroyed
What’s the 2nd Law of Thermodynamics?
The entropy or disorder of a system will always increase, not decrease
What’s the 3rd Law of Thermodynamics?
The entropy of a perfect crystal at a temperature of absolute zero will be zero.
According to the 2nd Law, does heat move from hot systems to cold systems, or cold systems to hot systems?
Heat moves from hot systems to cold systems to seek equilibrium
Conduction, convection, and radiation are examples of what?
Transfers of thermal energy
