Answer
(a) The minimum tension is 735 N
The maximum tension is 990 N
(b) The tension 3/4th of the way up the chain is 926 N
Work Step by Step
(a) Let $m_b$ be the mass of the ball.
Let $m_c$ be the mass of the chain.
The minimum tension in the chain is just above the wrecking ball.
$T = (m_b)~g = (75.0~kg)(9.80~m/s^2) = 735~N$
The maximum tension in the chain is at the top of the chain.
$T = (m_b+m_c)g = (75.0~kg+ 26.0~kg)(9.80~m/s^2) = 990~N$
(b) We can find the tension 3/4th of the way up the chain.
$T = (m_b+0.75\times m_c)g = (75.0~kg+ 19.5~kg)(9.80~m/s^2) = 926~N$
