Chapter 6
Which direction of torque is positive?
counter-clockwise about the axis
Which direction does the acceleration vector point in circular motion?
Towards the center of the circle
What does a negative velocity indicate?
Motion in the opposite direction
Define work and heat.
Work- A process that transfers energy to or from a system by mechanical means
Heat- a process that transfers energy to or from a system by thermal means
What is the ideal gas law?
PV= nRT
What is torque?
The rotational equivalent of force/ability of force to cause rotation
Define period and frequency.
Period- time it takes an object to go around a circle one time, completing a revolution
Frequency- number of revolutions per second, 1/T
What is impulse?
Impulse of a force is the product of the average force and the time interval during which the force acts; vector quantity has the same direction as the average force
Define kinetic and gravitational potential energy.
Kinetic- Energy of motion, KE= 1/2mv2
Potential- interaction energy associated with gravitational interaction between two masses, UG= mgh
Define isobaric, isochoric, isothermal, and adiabatic.
Isobaric- constant pressure
Isochoric- constant volume
Isothermal- constant temperature
Adiabatic- no transfer of heat
What is a mechanical advantage?
How many times larger the force of a simple machine exerts than the force you exert in using it.
- Cheater bar/nutcracker
What is centrifugal force?
Not a real force; what you feel is your body trying to move in a straight line as outside forces act to turn you into a circle
What is the Impulse-Momentum Theorem?
When a net force acts on an object, the impulse of this force is equal to the change in the momentum of the object
What is power?
Power- rate at which energy is transferred or transformed, rate of doing work
Define the phase constant.
Φ0 , different values of the phase constant correspond to different starting points on the circle and thus to different initial conditions
What factors impact the ability of a force to cause rotation?
Magnitude F of the force
Distance r from pivot point
The angle at which force is applied
How are angular kinematic equations for rotational motion with constant angular acceleration similar to kinematics for linear motion?
Same equations, different constants
What is conservation of momentum?
If the sum of external forces is zero, the total linear momentum in an isolated system is constant. (Initial and final momentum are the same)
How does friction impact motion?
Mechanical energy is not conserved, initial mechanical energy = final mechanical energy + thermal energy
What is the ideal spring law.
F= kx
What are the two ways to calculate torque?
FT = F sin Φ
rT = r sin Φ
Explain the rigid body model
Approximation for stiff objects, either translate, rotate, or combine
What is the difference between elastic and inelastic collisions?
Elastic- kinetic energy is conserved
Inelastic- KE not conserved, objects “stick” together
What is the Basic Energy Model?
Energy is a property of the system
Only forms of energy are kinetic, potential, and thermal. The only energy transfer mechanism is work.
Energy is transformed within the system without loss. (Conservation of energy)
Energy is transferred to and from the system by forces from the environment
Define simple harmonic motion, amplitude, and hertz.
Simple harmonic motion- sinusoidal oscillation
Amplitude- distance from the axis to the maximum or minimum
Hert- number of cycles per second