Physics semester exam
The force of friction on a sliding object is 10 N the applied force needed to maintain a constant velocity is
10 N
A man weighing 800N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is
400N
Disregarding air resistance objects fall with constant
Acceleration
According to Newton's law of inertia, a railroad train in motion should continue going forever even if its engine is turned off. We never observe this because railroad trains
Always have forces that oppose their motion
If the volume of an object were to double while its mass stays the same its density would
Be cut in half
When weight is applied to the stone arch, all of the stone blocks in the arch undergo
Compression
If the mass of an object does not change a constant net force on the object produces
Constant accleration
If no external forces are acting on a moving object, it will
Continue moving at the same velocity
The two measurements necessary for calculating average speed are
Distance and Time
Chemical properties of matters come mostly from its
Electrons
Whirl a rock at the end of a string and it follows a circular path, if the string breaks the tendency of the rock is to
Follow a straight line path
The Newton (N) is a unit of
Force
If your automobile runs out of fuel while you are driving, you do not come to an abrupt stop. The concept that most explains why is
Inertia
When a chocolate bar is cut in half its density
Is unchanged
A kilogram is a measure of a objects
Mass
The reason a granite block is mostly empty space is that the atoms of the granite are
Mostly empty space themselves
The buoyant force on a rock is least when the rock is submerged
Partly ((((((==
The reason a life jacket helps you float is
The density of both you and the jacket together is less then your density alone
Your weight is
The gravitational attraction force between you and earth
While an object near the earth is in free fall its
Velocity increases
A completely submerged object always displaces its own
Volume of fluid
A car maintains a constant velocity of 100 km/hr for 10 seconds. During this interval its acceleration is
Zero0
A package falls off a truck that is moving at 30 m/s. Neglecting air resistance, the horizontal speed of the package just before it hits the ground is
about 30 m/s
_____________ is not a compound
air
as a helium filled balloon rises in the air, it becomes
bigger
in a vacuum, an object has no
buoyant force
an object is placed exactly halfway between the earth and the earth and moon. the object will fall toward the
earth
According to Kepler's law the paths of the planets about the sun are
ellipses
lobsters live on the bottom of the ocean. the density of a lobster is
greater than the density of sea water
the way that ocean tides exist is that the pull of the moon
is greater on oceans closer to the moon and less on oceans farther from the moon
Solid matter is mostly empty spaced the reason solids don't fall through one another is because
of ELECTRICAL FORCES
in an electrically neutral atom, the number of protons in the nucleus is balanced is balanced by an equal number of
orbital electrons
acceleration is great for a satellite when it is at the
perigee
In our part of the universe anti-matter is
short lived
if an astronaut landed on a planet made of antimatter, there would be an explosion and
the astronaut and a an equal amount of the planet would both annihilate
Compared to the energy it takes to separate oxygen and hydrogen from water, the amount of energy given off when they recombine is
the same
the speeds of the planets about the sun depend on
their distances from the sun
Planets would crash into the sun if it weren't for
their tangential velocities
the density of a submerged submarine is about the same as the density of
water
A fish normally displaces its own
weight and volume of water
atmospheric pressure is caused by the
weight of the atmosphere