Two blocks of masses 20 kg and 8.0 kg are connected together by a light string and rest on a frictionless,level surface.Attached to the 8.0-kg mass is a second light string,which a person uses to pull both blocks horizontally.If the two-block system accelerates at 1.0 m/s²,what is the tension in the second string attached to the 8.0-kg mass? A) 14 N B) 6.0 N C) 28 N D) 4.0 N

Question

Quizplus · Accepted Answer

We can begin by using Newton's Second Law to find the net force acting on the two-block system:
F_net = (m_1 + m_2) * a
where m_1 and m_2 are the masses of the two blocks, and a is the acceleration. Substituting the given values, we have:
F_net = (20 kg + 8.0 kg) * 1.0 m/s^2 = 28 N
Since the surface is frictionless, the tension in both strings is the same:
T = F_net = 28 N
However, we need to find the tension in the second string attached to the 8.0-kg mass. We can consider only this block and apply Newton's Second Law:
T - m_2 * g = m_2 * a
where g is the acceleration due to gravity. Since the block is on a level surface, g = 0, so we have:
T = m_2 * a
Substituting the values, we get:
T = 8.0 kg * 1.0 m/s^2 = 8.0 N
Therefore, the correct answer is: 
Choice C (28 N)

Two Blocks of Masses 20 Kg and 8