問題一覧
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is a vector quantity that has magnitude and is directed along the axis of rotation
angular momentum
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measures the time rate of a change of velocity average acceleration=change in velocity vectors/time taken
acceleration
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is the gravitational force acting downward on the object. on the earth it is gravitational force exerted on the object by the planet. its unit are newtons in the SI and pounds in the british system
weight
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is the tendency of a body at rest to remain at rest, end of a body in motion to continue moving with unchanged velocity
inertia
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it can neither be created nor destroyed, but only transform from one kind to another
energy
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is a thermal energy in transit from a system at one temperature to a system that is in contact with it, but is at lower temperature
heat
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it is an object at a certain time is the slope of a velocity versus time graph at that time
instantaneous acceleration
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an object at rest will remain at rest; an object in motion will continue in motion with constant velocity, except in so far as it's acted upon by an external force.
newton's first law
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is usually expressed in radians, in degrees, or in revolutions
angular displacement
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is the product of a force and the time interval over which the force acts
impulse
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acting on an object causes the object to accelerate in the direction of that force
net external force
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is defined for the case in which one surface is just on the verge of sliding across another surface
coefficient of static friction
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describe the shape elasticity of a material.
shear modulus
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originally contain two parts. it's first part was simply the defining equation for resistance V = IR.
ohm's law
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has a magnitude torque times time worthy is the time during which the constant torque acts on the object
angular impulse
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is a tangential force acting on an object that opposes the sliding of the object on adjacent surface with which it in contact. it is parallel to the surface and opposite to the direction of the motion or of impending motion
friction force
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is the product of its mass and velocity
linear momentum
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is one in which the sum of the translational KEs of the object is not changed during the collision
perfectly elastic collision
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whose axis of rotation is fixed is the rate at which its angular coordinate, the angular displacement, changes with time
angular speed
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are forces whose lines of action all pass through a common point. the forces acting on it point object because they all pass through the same point, the point object.
concurrent forces
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done on a rotating body during an angular displacement by a constant torque is even by W= torque(teta)
work
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is one that has nothing to do with a special direction. many physical concept such as length time temperature mass density charge and volume are scalars; each has a scale or size but no associated direction.
scalar quantity
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is the modulus of elasticity
young's modulus
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what is the si unit of power
watt
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is the point at which the entire weight of the object may be considered concentrated
center of gravity
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it is effective value in a given direction. for example the x component of a displacement is the displacement parallel to the x-axis caused by the given displacement.
component of a vector
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describe the volume elasticity of a material. suppose that i uniformly distributed comprehensive force acts on the surface of an object and is directed perpendicular to the surface at all points
bulk modulus
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what is the units of torque
newtons-meters
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is the quantity of heat required to change the temperature of unit mass of the substance by 1°
specific heat
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either the direction may be chosen as positive. if a displacement velocity or acceleration is in the opposite direction. it must be taken as _____________.
negative
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a body woolly or partly immerse in a fluid is buoyed up by a force equal to the weight of the fluid it deplays. it can be considered to act vertically upward through the center of the gravity of the displace fluid
archimedes' principle
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a torque that tends to cause counterclockwise rotation about the axis is
positive
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experience within a solid is the magnitude of the force acting, divided by the area over which it acts
stress
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it is a newton's law that matter interact with matter--forces come in pairs. this is often called the law of action and reaction
newton's third law
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is a measure of the rotational inertia of the body. if an object that is free to rotate about an axis is difficult to set into rotation
moment of inertia
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is the time rate of doing work or the rate of transfer of energy
power
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is the energy possessed by an object because it is in motion. if an object of mass m is moving with a speed v, it has translational KE
kinetic energy
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the fluid flow through a cylindrical pipe of length and cross sectional radius is given by
poiseuille's law
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is a dimensionless number that applies to a fluid of viscosity and density flowing with speed through a pipe with diameter
reynolds number
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is a vector quantity whose direction is that of the velocity. the unit are kg•m/s
momentum
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the torque the tense to cause clockwise rotation about the axis is
negative
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the moment of inertia of a body about an axis parallel to an axis through the center of a mass
parallel-axis theorem
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each vector is dissolved into x -, y -, nc components, with negatively directed components taken as negative
component method
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about an axis, due to a force, is a measure of the effectiveness of the force in producing rotation about that axis.
torque
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is the random kinetic energy of the particles (usually electrons ions atoms and molecules) composing a system
thermal energy
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is a source of electrical energy
battery
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is defined for the case in which one surface is sliding across another at constant speed
coefficient of kinetic friction
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is an object whose mass is defined to be 1 kg. the masses of other object are found by comparison with this mass. a gram mass is equivalent to exactly 0.001 kg
standard kilogram
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are defined in the relation to a right angle.
trigonometric function
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for the study flow of a continuous stream of fluid: considered two different points along the stream path
bernoulli's equation
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when two masses m and m' gravitationally interact, they interact each other with forces of equal magnitude. for point masses or spherically symmetric bodies, the attractive force Fg is given by FG=G mm'/r²
law of universal gravitation
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is the force that must act on a mass moving in circular path of radius to give it the centripetal acceleration
centripetal force
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the si unit of mass density
kg/m³
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is a measure of the change imparted to a system. it is given to an object when a force does work on the object
energy
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falling freely toward the earth's in subject to only one force
mass
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is essentially the force with which gravity pulls downward upon it
weight
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is the property by which of body returns to its original size and shape when the forces that deform it are removed
elasticity
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is the smallest stress that will produce a permanent distortion in the body. when a stress in excess of this limit is applied, the body will not return exactly to its original state after the stress is removed
elastic limit
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when an object moves from one point in space to another the displacement is the vector from the initial location to the final location. it is independent of the actual distance travel
displacement
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this method for finding the resultant of a several vectors consists in beginning at any convenient point and drawing each vector arrow in turn in they may be taken in any order of succession the tail end of each arrow is position at the tip end of the proceeding one
graphical addition of vectors
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is the average velocity evaluated for a time interval that approaches zero
instantaneous velocity
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it is from a wire or other object is measure of the potential difference that must be impressed across the object to cause a current of 1 ampere to flow through it
resistance
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what is the standard atmospheric pressure
1.01×10⁵ Pa
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the acceleration of a body moving only under the force of gravity, which is directed vertically downward
gravitational
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what is the si unit of pressure
Pascal
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scale is displaced 273.15 celsius
kelvin
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suppose that attack contains liquid and is open to the atmosphere at its top
torricelli's theorem
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acting on a body of moment of inertia, produces in it an angular acceleration
torque and angular acceleration
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is a vector quantity. if an object undergoes a vector displacement s in a time interval t then average velocity equals vector displacement over time taken
velocity
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p of a material it is mass per unit volume
mass density
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is the rate at which the shares train within the fluid is changing
shear rate
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the _________ of an object is measure of the inertia of the object
mass
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is the energy possessed by an object because of the gravitational interaction
gravitational potential energy
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due to a column of fluid of height and mass density
hydrostatic pressure
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maybe measured on the celsius scale, on which the freezing point of water is 0° c, and the boiling point is at 100° c
temperature
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the si unit of work
newton-meter
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whose axis of rotation is fixed in the rate at which its angular speed changes with time
angular acceleration
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transmitted to a body by a torque is given by P=(torque)(angular speed)
power
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when the pressure on any part of a confined fluid liquid or gas is changed, the pressure and every other part of the fluid is also changed by the same amount
pascal's principle
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is the agency of change. in mechanics it is that which changes the velocity of an object. it is a vector quantity having magnitude and direction
force
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have a magnitude of 1 and are represented by the bold face symbol top with a caret
unit vectors
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is a scalar quantity. if an object takes a time interval t to travel a distance l, then average speed equals total distance travel over time taken
speed
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is the ratio of the density of the substance to the density of some standard substance. It is usually water (4°C) for liquids and solids while for gases, it is usually air
specific gravity
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the magnitude of the tensile force
tension
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when a fluid that fills in a pipe flows through the pipe with an average speed
flow or discharge
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done by a force is defined as the product of that force times the parallel distance over which it acts.
work
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it is a fluid that measure of how large a shear stress is required to produce unit shear rate
viscosity
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is one that has be specified completely only if we provide both its magnitude (size) and direction. many physical concepts such as displacement velocity acceleration force and momentum are vector quantities.
vector quantity
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in electricity exist in a region when a net electric charge is transported from one point to another in that region
current
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for any collision between two bodies in which the body's move only along a single straight line
coefficient of restitution
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is the fractional deformation resulting from a stress. it is measured as the ratio of the change in some dimension of the body to the original dimension in which the change occurred
strain
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under the action of concurrent forces provide it is not accelerating
equilibrium
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what is the si unit for stress
pascal
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acting on a string or chain or tendon is the applied force tending to stretch it.
tensile force
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is one whose source lies outside of the system being considered
external force
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a point mass m moving with constant speed v around a circle of radius is undergoing acceleration. although the magnitude of its linear velocity is not changing, the direction of the velocity is continually changing
centripetal acceleration
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is a constant and lies along the line of displacement vector
acceleration vector
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on an object that is being supported by the surface is the component of the supporting force that is perpendicular to the surface
normal force