A2L Item 126

Goal: Problem solving

Source: UMPERG-ctqpe23

If m2 = 2m1 , m3 = 3m1 and
the force that the surface exerts on the bottom block is 120N, the mass
of the large block is

Use g = 10 N/kg.

  1. 2 kg
  2. 4 kg
  3. 6 kg
  4. 8 kg
  5. 12 kg
  6. 20 kg
  7. none of the above

Commentary:

Answer

(3) the most common other answers are #1 and #6, each of which
represents a typical mistake students make. This problem presents a good
opportunity to encourage students to check their answer.