Answer:
False
Explanation:
ionic particles, which are hydrophilic, cannot easily cross a membrane. Very small polar molecules, such as water, can cross via simple diffusion due to their small size. Charged atoms or molecules of any size cannot cross the cell membrane via simple diffusion as the charges are repelled. Because these ions can cross the cell membrane, their movement is restricted to protein channels and specialized transport mechanisms in the membrane.
<span>A, B, and C are correct descriptions.
Choice-D does NOT accurately describe the forces
that exist within an atom.
Choice-D should say:
"Electrons positioned closer to the nucleus have a greater
attraction to the protons and are LESS likely to be discharged
from the atom than electrons farther away are."</span>
With its apparent magnitude
Answer:
Approximately
if that athlete jumped up at
. (Assuming that
.)
Explanation:
The momentum
of an object is the product of its mass
and its velocity
. That is:
.
Before the jump, the speed of the athlete and the earth would be zero (relative to each other.) That is:
and
. Therefore:
and
.
Assume that there is no force from outside of the earth (and the athlete) acting on the two. Momentum should be conserved at the instant that the athlete jumped up from the earth.
Before the jump, the sum of the momentum of the athlete and the earth was zero. Because momentum is conserved, the sum of the momentum of the two objects after the jump should also be zero. That is:
.
Therefore:
.
.
Rewrite this equation to find an expression for
, the speed of the earth after the jump:
.
The mass of the athlete needs to be calculated from the weight of this athlete. Assume that the gravitational field strength is
.
.
Calculate
using
and
values from the question:
.
The negative sign suggests that the earth would move downwards after the jump. The speed of the motion would be approximately
.
X-ray)
because Electromagnetic waves are in act