An electron is placed in a magnetic field that is directed along a z axis. The energy difference between parallel and antiparall
1 answer:
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Explanation:
Given that,
A ball is tossed straight up with an initial speed of 30 m/s
We need to find the height it will go and the time it takes in the air.
At its maximum height, its final speed, v = 0 and it will move under the action of gravity. Using equation of motion :
v = u +at
Here, a = -g
v = u -gt
i.e. u = gt
So, the time for upward motion is 3.06 seconds. It means that it will in air for 3.06×2 = 6.12 seconds
Let d is the maximum distance covered by it.
Putting all values
Hence, it will go to a height of 45.91 m and it will in the air for 6.12 seconds.
Answer:
The percentage uncertainty in the average speed is 0.10% (2 sig. fig.)
Explanation:
Consider the formula for average speed .
,
where
is the total distance, and
is the time taken.
The percentage uncertainty of a fraction is the sum of percentage uncertainties in
- the numerator, and
- the denominator.
What are the percentage uncertainties in and
in this question?
The unit of the absolute uncertainty in is meters. Thus, convert the unit of
to meters:
.
.
The unit of the absolute uncertainty in is seconds. Convert the unit of
to seconds:
Similarly,
.
The average speed here is a fraction of
and
. Both
and
come with uncertainty. The percentage uncertainty in
will be the sum of percentage uncertainties in
and
. That is:
.
Generally, keep
- two significant figures for percentage uncertainties that are less than 2%, and
- one for those that are greater than 2%.
The percentage uncertainty in here is less than 2%. Thus, keep two significant figures. However, keep more significant figures than that in calculations to make sure that the final result is accurate.