At 9 a.m. on Monday a radioactive sample contained four million ...

[justinmsk]

At 9 a.m. on Monday a radioactive sample contained four million nuclei. At 9 a.m. on Friday three million of these nuclei had decayed. The half-life of this sample is:
 a. 5 days b. 4 days c. 3 days d. 2 days e. 1 day

Question 2

An airplane flies in a horizontal circle of radius 500 m at a speed of 150 m/s. If the radius were changed to 1 000 m, but the speed remained the same, by what factor would its centripetal acceleration change?
 a. 0.25
  b. 0.50
  c. 1.00
  d. 2.00
  e. 4.00

[mcinincha279]

Answer to Question 1

d

Answer to Question 2

B

[justinmsk]

Excellent

[hollysheppard095]

Gracias!