Answer:
After 1 half-life (500 years), 500 g of the parent isotope will remain. After 2 half-lives (1000 years), 250 g of the parent isotope will remain. After 3 half-lives (1500 years), 125 g of the parent isotope will remain. After 4 half-lives (2000 years), 62.5 g of the parent isotope will remain.
Explanation:
A period is a form of grammer , and it is used to end a sentence
Answer:

Explanation:
The equation for the linear impulse is as follows:

where
is impulse,
is the force, and
is the change in time.
The force, according to Newton's second law:

and since 
the force will be:

replacing in the equation for impulse:

we see that
is canceled, so

And according to the problem
,
and the mass of the passenger is
. Thus:



the magnitude of the linear impulse experienced the passenger is 
(a) 6.04 rev/s
The speed of the ball is given by:

where
is the angular speed
r is the distance of the ball from the centre of the circle
In situation 1), we have

r = 0.600 m
So the speed of the ball is

In situation 2), we have

r = 0.900 m
So the speed of the ball is

So, the ball has greater speed when rotating at 6.04 rev/s.
(b) 
The centripetal acceleration of the ball is given by

where
v is the speed
r is the distance of the ball from the centre of the trajectory
For situation 1),
v = 30.6 m/s
r = 0.600 m
So the centripetal acceleration is

(c) 
For situation 2 we have
v = 34.1 m/s
r = 0.900 m
So the centripetal acceleration is
