Linear & Projectile Motion
when an object slows down, its acceleration is______
negative
According to Netwon's Third Law: if you push gently on something, it will push_____
gently on you
Two train cars having the same mass and speeds move toward each other on a track and stick together. After the collision velocity of the two train cars is
0 m/s
Using a force to cause a body to move in the direction of the force is called
work
The heat transfer process where warm gases rise and cool gases sink causing circulation (like in a lava lamp) (this form of heat transfer is the driving force in our weather)
convection
acceleration is ______
a measure of how fast velocity is changing (m/s/s), when velocity is constant, acceleration is zero
As a ball falls towards the Earth, the action force is the pull of the Earth's mass on the ball. What is the reaction force?
the pull of the ball's mass against the earth
A rifle recoils from firing a bullet. The speed of the rifle’s recoil is small because
rifle has more mass than the bullet
The ratio of useful work output to total work input is called the
efficiency
The heat transfer type where heat travels in waves.
radiation
velocity is a ________ quantity meaning it has magnitude and direction; speed is a ______ quantity, meaning it has magnitude but direction is irrelevant
A woman weighing 500N sits on the floor. The floor exerts a force on the woman of
500 N
The momentum of a system is conserved only when
there is no net external force acting on the system
The ratio of output force to input force of a simple machine is called the
mechanical advantage
Which type of heat transfer occurs when heat is transferred from one molecule to the next?
conduction (conductors- good at heat transfer; insulators- bad at heat transfer )
motion along a curved path would be called ________ motion, and motion along a straight line path would be called ______ motion
non-linear; linear
pressure is defined as
force/area (unit-pascal)
An ice skater moves toward another stationary skater. The moving skater jumps into the stationary skater’s arms and both skaters move together. The momentum of the two skaters together is
the same as the momentum of the first skater before the collision (double mass, half velocity)
Which has greater kinetic energy, a car traveling at 30 km/h or a half-as-massive car traveling at 60 km/h?
smaller car (KE=1/2mv2- much more dependent on velocity than mass)
Heat always flows from areas of _____ temperature to areas of _____ temperature until _______
high; low; thermal equilibrium is reached (uniform temp)
when an object reaches it's terminal velocity, its acceleration is _______
A 10 N falling object encounters 4 N of air resistance. What is the net force acting on the object?
6 N
Compared to a sports car moving at 30 m/s, a sports car weighing half as much and moving at 30 m/s has ______ the momentum
half
A job is done slowly, and an identical job is done quickly. Both jobs require the same amount of work but different amounts of
power
_____ energy is created by the flow of electrons, _____ energy is the sun's energy that travels in waves, ______ energy is released during chemical reactions, _______ energy is from fission or fusion of atoms, _____ is heat energy, and _______ is energy motion or potential motion
electrical; radiant; chemical; nuclear; thermal; mechanical