CONCEPTUAL PHYSICS CH13 CORRECT
DETAILED ANSWERS.
When you stand on one foot instead of two, the force you exert on the floor
is
A) less.
B) the same.
C) more.
D) None of the above. - CorreCt Answers -B) the same.
Two solid blocks of identical size are submerged in water. One block is lead
and the other is aluminum. Upon which is the buoyant force greater? -
CorreCt Answers -The buoyant force is the same on each block because
they displace the same volume of water. For submerged objects, buoyant
force is determined only by the volume of water displaced, not the object's
weight.
If a fish makes itself denser, it will sink; if it makes itself less dense, it will
rise. In terms of buoyant force, why is this so? - CorreCt Answers -When the
fish decreases its volume, it displaces less water, so the buoyant force
decreases. When the fish expands its volume, the buoyant force increases.
Why is it easier for you to float in saltwater than in freshwater? - CorreCt
Answers -Saltwater is denser than freshwater, which means you don't"sink"
as far when displacing your weight. You'd float even higher in mercury
(density 13.6 g/(m~), and you'd sink completely in alcohol (density 0.8
g/cm3).
, A river barge loaded with gravel approaches a low bridge that it cannot
quite pass under. Should gravel be removed from or added to the barge? -
CorreCt Answers -? gravel should be added ?
As the automobile on a lift is being lifted, how does the change in oil level in
the reservoir compare with the distance the automobile moves? - CorreCt
Answers -The car moves up a greater distance than the oil level drops, since
the area of the piston is smaller than the surface area of the oil in the
reservoir.
If a friend commented that a hydraulic device is a common way of
multiplying energy. what would you say? - CorreCt Answers -No, no, no!
Although a hydraulic device, like a mechanical lever, can multiply force it
always does so at the expense of distance. Energy is the product of force
and distance, if you increase one,you decrease the other. No device has ever
been found that can multiply energy!
If a block of oak with 75% the density of water is placed in a bucket of
water, what percentage of the wood will be above water?
A) 75%
B) 100%, because it will float
C) 25%
D) it is impossible to tell without knowing the density of water.
E) 0% because oak is heavy enough to sink. - CorreCt Answers -C) 25%
All ice floats. This tells you that
A) the solid form of water is less dense than the liquid form.
B) ice must always be filled with air bubbles.
DETAILED ANSWERS.
When you stand on one foot instead of two, the force you exert on the floor
is
A) less.
B) the same.
C) more.
D) None of the above. - CorreCt Answers -B) the same.
Two solid blocks of identical size are submerged in water. One block is lead
and the other is aluminum. Upon which is the buoyant force greater? -
CorreCt Answers -The buoyant force is the same on each block because
they displace the same volume of water. For submerged objects, buoyant
force is determined only by the volume of water displaced, not the object's
weight.
If a fish makes itself denser, it will sink; if it makes itself less dense, it will
rise. In terms of buoyant force, why is this so? - CorreCt Answers -When the
fish decreases its volume, it displaces less water, so the buoyant force
decreases. When the fish expands its volume, the buoyant force increases.
Why is it easier for you to float in saltwater than in freshwater? - CorreCt
Answers -Saltwater is denser than freshwater, which means you don't"sink"
as far when displacing your weight. You'd float even higher in mercury
(density 13.6 g/(m~), and you'd sink completely in alcohol (density 0.8
g/cm3).
, A river barge loaded with gravel approaches a low bridge that it cannot
quite pass under. Should gravel be removed from or added to the barge? -
CorreCt Answers -? gravel should be added ?
As the automobile on a lift is being lifted, how does the change in oil level in
the reservoir compare with the distance the automobile moves? - CorreCt
Answers -The car moves up a greater distance than the oil level drops, since
the area of the piston is smaller than the surface area of the oil in the
reservoir.
If a friend commented that a hydraulic device is a common way of
multiplying energy. what would you say? - CorreCt Answers -No, no, no!
Although a hydraulic device, like a mechanical lever, can multiply force it
always does so at the expense of distance. Energy is the product of force
and distance, if you increase one,you decrease the other. No device has ever
been found that can multiply energy!
If a block of oak with 75% the density of water is placed in a bucket of
water, what percentage of the wood will be above water?
A) 75%
B) 100%, because it will float
C) 25%
D) it is impossible to tell without knowing the density of water.
E) 0% because oak is heavy enough to sink. - CorreCt Answers -C) 25%
All ice floats. This tells you that
A) the solid form of water is less dense than the liquid form.
B) ice must always be filled with air bubbles.
