An air sample is contaminated with 15O, which has a half-life of ...

[Caiter2013]

An air sample is contaminated with 15O, which has a half-life of 2.03 min.
 
  One possible way to minimize its hazard is to pass it through a long pipe to allow it to decay inside the pipe until it can be safely released into the atmosphere. If the oxygen moves at a speed of 1.1 m/s in the pipe, how long must the pipe be for the sample to have decayed to 3.0 of its original activity just as it leaves the pipe?
  A) 8.0 m B) 680 m C) 7.0 m D) 2.0 m

Question 2

A 0.140-kg baseball is dropped and reaches a speed of 1.20 m/s just before it hits the ground. It rebounds with a speed of 1.00 m/s. What is the change of the ball's momentum?
 
  A)
 
  0.0280 kgm/s upwards
  B)
 
  0.0280 kgm/s downwards
  C)
 
  0.308 kgm/s upwards
  D)
 
  0.308 kgm/s downwards
  E)
 
  0 kgm/s

[uniquea123]

Answer to Question 1

B

Answer to Question 2

C

[Caiter2013]

Excellent

[brbarasa]

Gracias!