Answer:
10ms
Explanation:
The bird must travel the length of the train (150m), with a combined speed of 15m/s this means it will take 10s to cross an accumulated 150ms.
Answer:
30,000 units, because total energy remains unchanged
75.17 mg of the radioactive substance will remain after 24 hours.
Answer:
Explanation:
Any radioactive substance will obey the exponential decay behavior. So according to this behavior, any radioactive substance will be decaying in terms of exponential form of disintegration constant and Time.
Disintegration constant is the rate of decay of radioactive elements. It can be measured using the half life time of the radioactive element .While half life time is the time taken by any radioactive element to decay half of its concentration. Like in this case, at first the scientist took 200 mg then after 17 hours, it got reduced to 100 g. So the half life time of this element is 17 hours.
Then Disintegration constant = 0.6932/Half Life time
Disintegration constant = 0.6932/17=0.041
Then as per the law of disintegration constant:

Here N is the amount of radioactive element remaining at time t and
is the initial amount of sample, x is the disintegration constant.
So here,
= 200 mg, x = 0.041 and t = 24 hrs.
N = 200 ×
=75.17 mg.
So 75.17 mg of the radioactive substance will remain after 24 hours.
C.
because centripetal means that force only acts in the center of body in motion