Physical Science Midterm
A 2-kg book is held 1 m above the floor for 50 s. The work done is
0
The mass of a 2,200-lb elephant is
1,000 kg
The prefix giga stands for
1,000,000,000
A person is 5 ft 8.0 in. tall. This is equivalent to
173 cm
The number of cubic centimeters in a cubic foot is about
2.8 x 10^4
A 50-kg person weighs
490 N
A 3000 kg truck accelerates from 10 m/s to 30 m/s in 8 s. The net force on the truck is
7500 N
Which of the following statements is not true?
The United States has less than 5 percent of the world's coal reserves
International agreements thus far
call for promises from all countries to reduce their use of fossil fuels
The sun exerts a gravitational force on the earth in the earth exerts a gravitational force on the sun. The force the earth exerts
can be considered either as the action or as the reaction force
Eventually, if bioethanol remains in use, it will probably be made from
cellulose
At the present, the source of most electricity from moving water is
dams in rivers
Of these sources, which is responsible for the most energy today?
hydropower
In most parts of the world high tides occur approximately
twice a day
The longest of the following is
0.00001 km
A meter is not equal to
0.01 km
A centimeter is
0.01 m
The shortest of the following is
0.1 mi.
A force that gives a 2-kg object an acceleration of 1.6 m/s^2 would give an 8-kg object an acceleration of
0.4 m/s^2
The time needed for a car whose speed is 60 km/h to travel 800 m is
0.8 min
A 1-N weight has a PE relative to the ground of 1 J when it is at a height of
1 m
A car whose mass is 1600 kg (including the driver) has a maximum acceleration of 1.2 m/s2. If three 80-kg passengers are also in the car, its maximum acceleration will be
1.04 m/s^2
A 90-kg llama has an advantage power output of 80 W. The minimum time the llama can go up a hill 500 m high is
1.5 h
A weightlifter raises a 200-kg barbell through a height of 2 m in 2.2 s. The average power he develops during the lift is
1.78 kW
The mechanical advantage of a pair of scissors might be
1/2
A total of 4900 J is expended in lifting a 50-kg mass. The mass is raised to a height of
10 m
The proportion of the world's electricity that comes from nuclear energy is roughly
10 percent
An airplane reaches its takeoff speed of 60 m/s in 30 seconds starting from rest. The time it spends in going from 40 m/s to 60 m/s is
10 s
A 40-kg boy climbs a vertical ladder at 0.5 m/s. His power output is
196 W
The size of a picture is given as 84 cm by 255 cm. Since (84)(255) = 2.142 exactly, the area of the picture is expressed with the correct number of significant figures as
2.1 m^2
After a stone dropped from a cliff has fallen 20 m, the stone speed is approximately
20 m/s
The mass of a sack of potatoes whose weight is 200 N is
20.4 kg
In a good wind, a modern large wind turbine might have a power output of
2000 kW
The linear momentum of a 400-kg giraffe galloping at 5 m/s is
2000 kgm/s
The minimum number of unequal forces whose vector sum can equal zero is
3
When a ton of coal burns, it loses 3.3 × 10^-7 kg of mass. The energy given off is
3.0 × 10^10 J
A 1200-kg car is traveling at 10 m/s on a road such that the maximum frictional force between its tires and the road is 4000 N. The minimum turning radius of the car is
30 m
The speed of a 1000-kg car whose KE IS 450 kJ is
30 m/s
The 2.5-kg head of an ax exerts a force of 80 kN as it penetrates 18mm into the trunk of a tree. The speed of the ax head when it strikes the tree is
34 m/s
Average energy use per person in the United States today is about
4 times the world average
A 1-N weight has a KE of 1 J when its speed is
4.4 m/s
When its brakes are applied, a car moving at 10 m/s undergoes an acceleration of -1.2 m/s^2. How far does the car travel before it comes to a stop?
42 m
The mass equivalent of 6.0 MJ is
6.7 x 10^-11 kg
A woman who is mass is 60 kg on the earth's surface is in a spacecraft at a height of 2 earth radii above the earth's surface. Her mass there is
60 kg
A car moving at 10 m/s undergoes an acceleration of 1.2 m/s^2. In the next 5 s the car travels
65 m
A planet that cannot be seen with the unaided eye is
Neptune
Newton is said to have discovered gravity under an apple tree when he should have been at college. Why?
Newton returned home from Trinity College to pursue his private study, as school was closed due to the Great Plague. Legend has it that, at this time, Newton experienced his famous inspiration of gravity with the falling apple.
Concerning the processes of science and technology, which comes first and why?
Science is the study of the natural world by collecting data through a systematic process called the scientific method. And technology is where we apply science to create devices that can solve problems and do tasks. Technology is literally the application of science.
Which of the following statements is true?
The moon is chiefly responsible for the tides, with the suns influence modifying the title range
A car whose speed is a steady 50 km/h
is accelerated when it climbs a hill, goes over the crest, and descends on the other side
The speed of a planet in its orbit
is highest when it is closest to the sun
When the speed v of an object of mass m approaches the speed of light c, its kinetic energy
is more than 1/2 mv^2 and can exceed 1/2 mc^2
Astrology
is nonsense
Why did Newton say his work was based on the work of giants before him?
it was because he was working in the light of discoveries made by fellow scientists, either in his own time or earlier
A hole is drilled to the center of the earth and a ball is dropped into it. When the ball is at the earth's center, compared with their respective values at the earth's surface,
its mass is the same and its weight is 0
A bullet is fired upward. As it rises,
its mass remains the same while its weight decreases
If a shell fired from a canon explodes in mid air,
its total KE increases
An object that has linear momentum must also have
kinetic energy
Which one or more of the following is a vector quantity?
linear momentum angular momentum
A jumper whose weight is w presses down on the floor with the force F and leaves the floor as a result. The force the floor exerted on the jumper was
more than w and equal to F
Scientific theories
must be constantly reviewed to see whether they are in accord with new experimental observations
Methane is the chief constituent of
natural gas
The fossil fuel least polluting to burn is
natural gas
The period of the earth's orbit around the sun is
one year
Since 1900 the world's population has increased by
over 400 percent
An unsolved problem for nuclear energy is
permanent waste disposal
What is the difference between philosophy and science?
philosophy is ideas and explanations from observations without experimentation science is the best explanation of its time using experimentation
A promising but expensive method of preventing the escape into the atmosphere of carbon dioxide from fossil fuel power plants is to
pump it into underground reservoirs
Gravity is not
responsible for holding atoms and molecules together
In the distant past, the length of the day was
shorter than 24 h
In which one or more of the following is the earth assumed to be the center of the universe
the Ptolemaic system
A day is the time needed for
the earth to turn completely on its axis
A year is the time needed for
the sun to migrate completely around the sky
An object moving in a circle at consistent speed is accelerated
toward the center of the circle
Solar radiation is ultimately responsible for
wind energy
If the earth were to revolve on its axis slower than it does today, its shape
would be closer to a perfect sphere
The renewable energy source that requires the most area for a given power output is
biofuel
In fracking, natural gas trapped in rock formations is released by
breaking up the rock with water under high pressure
To prevent it from tumbling in flight, a projectile such as a football is scent of spinning. The physical principle involved is
conservation of angular momentum
The time at which a given star rises above the horizon each night is
earlier than the night before
Aristotle's elements from lowest to highest
earth water air fire
Relative to the stars, the moon seems to move
eastward
The stars in a constellation
form a pattern in the sky as seen from the earth
The speed of an object moving in a circle is doubled. The centripetal force needed is
four times as much as before
If the moon were half as far from the earth as it is now, the gravitational force it exerts on the earth would be
four times its present value
What type of universe did Plato philosophize?
geocentric (everything goes around the earth)
In the United States, bioethanol from corn is added to gasoline for vehicle fuel because
government action favors its production and use
The weight of an object is
greater at the poles than at the equator
A stone is thrown upward from a roof at the same time as another, identical stone is dropped from there. The two stones
have the same acceleration when they reach the ground
What is the distinguishing feature of Tycho Brahe?
he had a copper nose and a bushy mustache
Why was Ptolemy's model to approach the problem of retrograde motion incorrect?
he modeled the planets making epicycles (small circles) around a point that orbited the Earth allowing the planets to move backward relative to the background stars we now know that the earth isn't the center, the planets' orbits aren't circular, and planets don't orbit within their orbit cycle
Environmental concerns are the most important factor in limiting the expansion of which of the following energy sources?
hydropower
When first proposed, a scientific idea is usually called a
hypothesis
How did Kepler change the model of Copernicus to allow it to work perfectly?
improved the heliocentric model by proposing that the planets moved around the Sun in elliptical orbits.
Why does Copernicus' view of the universe counter Plato's view of the universe?
Copernicus said the universe was heliocentric (sun-centered) when Plato said it was geocentric (earth-centered)
