The radioactive half-life of a material is the time for A) ...

[lak]

The radioactive half-life of a material is the time for
 
  A) half of an original quantity of the material to decay.
  B) its decay rate to reduce to half.
  C) both of these
  D) neither of these

Question 2

A 50.0-kg box is resting on a horizontal floor. A force of 250 N directed at an angle of 20.7 below the horizontal is applied to the box. The coefficient of kinetic friction between the box and the surface is 0.300.
 
  What is the acceleration of the box? A) 1.21 m/s2
  B) 1.77 m/s2
  C) 2.84 m/s2
  D) 3.54 m/s2
  E) 5.14 m/s2

[k2629]

Answer to Question 1

Answer: C

Answer to Question 2

A

[lak]

Thank you!

[k2629]

Always glad to help...