Question

4. A 10 kg plank 3 meters in length extends off the edge of a pirate ship so that only 0.5 m ?? remains on the deck. This is held in place by a 200 kq crate of rum sitting on top of the end of the plank on the deck. A 70 kg pirate is being forced to walk the plank. How far does he get from the deck before the plank tips and he falls?

Answer 1

mass of the plank is m_1 = 10kg mass of the crate is m_2 = 200kg mass of the pirate is m_3 = 70kg we have to caluculate the distance n if plunk is in balance the torques of all forces about point A will balance each other that is \r\n m_1 g times 1 + m_3 g times (x - 0.5) = m_2 g times 0.5 10 times 1 + 70 times (x - 0.5) = 200 times 0.5 10 + 70x - 35 = 100 70x - 25 = 100 70x = 125 x = 125/70 x = 1.785m