Answer:
The existance of dark energy was suggested to help explain measurements, using Type Ia supernovae as distance indicators, that the expansion of the universe is speeding up and its acceleration requires a source of energy. Scientists suggested that It may be a new form of energy for which there is not yet a theoretical explanation. quantum mechanics predict that it may be the vacuum energy associated with "empty" space itself.
Answer:
this statement describes meteor's velocity,
because velocity is a vector quantity which has both magnitude as well as a specific direction and here the meteor's direction is specified in the statement hence we conclude that this statement describes meteor's velocity as well as speed too.
Answer:
Explanation:
The voltage of a disconnected charged capacitor increases when the plate area is decreased.
When plate area decreases , capacitance C decreases , but charge Q remains constant .
Q = C V where C is capacitance and V is voltage .
when C decreases , V increases for keeping Q constant .
So the statement is true.
The electric field is dependent on the charge density on the plates.
This statement is true .
The voltage of a connected charged capacitor remains the same when the plate area is decreased .
For a connected capacitor , V or voltage is constant which is equal to voltage of charging battery .
So the statement is true .
Sure. The acceleration may be decreasing, but as long as it stays
in the same direction as the velocity, the velocity increases.
I think you meant to ask whether the body can have increasing velocity
with negative acceleration. That answer isn't simple either.
If the body's velocity is in the positive direction, then positive acceleration
means speeding up, and negative acceleration means slowing down.
BUT ... If the body's velocity is in the negative direction, then positive
acceleration means slowing down, and negative acceleration means
speeding up.
I know that's confusing.
-- Take a piece of scratch paper, write a 'plus' sign at one edge and
a 'minus' sign at the other edge. Those are the definitions of which
direction is positive and which direction is negative.
-- Then sketch some cars ... one traveling in the positive direction, and
one driving in the negative direction. Those are the directions of the
velocities.
-- Now, one car at a time:
. . . . . first push on the back of the car, in the direction it's moving;.
. . . . . then push on the front of the car, against its motion.
Each push causes the car to accelerate in the direction of the push.
When you see it on paper, all the positive and negative velocities
and accelerations will come clear for you.
Answer: small cars can stop and go fast big trucks can not
Explanation:
