A2L Item 011

  • warning: Parameter 1 to theme_field() expected to be a reference, value given in /home/ibeatty/clickercentral.net/includes/theme.inc on line 171.
  • warning: Parameter 1 to theme_field() expected to be a reference, value given in /home/ibeatty/clickercentral.net/includes/theme.inc on line 171.
  • warning: Parameter 1 to theme_field() expected to be a reference, value given in /home/ibeatty/clickercentral.net/includes/theme.inc on line 171.
  • warning: Parameter 1 to theme_field() expected to be a reference, value given in /home/ibeatty/clickercentral.net/includes/theme.inc on line 171.
  • warning: Parameter 1 to theme_field() expected to be a reference, value given in /home/ibeatty/clickercentral.net/includes/theme.inc on line 171.
  • warning: Parameter 1 to theme_field() expected to be a reference, value given in /home/ibeatty/clickercentral.net/includes/theme.inc on line 171.

In order to solve the problem:

An airplane accelerates down a runway in order to take off but aborts and applies brakes causing the plane to stop. The plane speeds up at a constant rate for 5 seconds, then slows down at the same rate when the brakes are applied. The plane stops at a point that is 100 meters from its initial position. What was the acceleration of the airplane during the first 5 seconds?

Someone suggests the following procedure:

(A) The acceleration of the plane is constant and the same for the entire motion.

(B) The entire process takes 10 seconds and the displacement is 100 meters.

(C) It is possible, therefore, to use the formula “change in x = vo,x t + 1/2 ax t2”, where vo,x is zero and t = 10s.

(D) The only unknown in this equation is ax, so solve for it.

Which of the following is true?

  1. The procedure is invalid because statement A is incorrect.
  2. The procedure is invalid because statement B is incorrect.
  3. The procedure is invalid because statement C is incorrect.
  4. The procedure is invalid because statement D is incorrect.
  5. The procedure is invalid because more than one statement is incorrect.
  6. The procedure is valid.