PHYSICS BLOCK, FRICTION, NET FORCE

Question

Three blocks are lined up next to each other on a level frictionless table. From left to right, call them blocks A, B, and C. The blocks have masses, from left to right, of 2.0 kg, 4.0 kg, and 18.0 kg. All three blocks are pushed to the right by a horizontal 12 N force applied to the 2.0 kg block. What is the net force on block A?

Answer 1

Acceleration

F = 12 N = (m_A + m_B + m_C)a = 24a

a = F/(m_A + m_B + m_C) = (12 N)/(24 kg)

= ½ m/s²

Net Force on Each Block

F = ma = m(½)

Block A: m_A = 2 kg, so F_A = (2)(½) = 1 N

Block B: m_B = 4 kg, so F_B = (4)(½) = 2 N

Block C: m_C = 18 kg, so F_C = (18)(½) = 9 N

Answer

The net force on Block A is 1 N