Review I Constants Periodic Table the tension in the cable is equal to mg because tension and gravity are the only forces and they balance. Wrecking balls are used to demolish old buildings. A 760 kg steel ball is suspended from a 10-m-long cable on a crane. A hook on the crane slowly pulls the ball back, then releases it. The ball's speed at the lowest point in its arc, just before striking the building, is 4.5 m/s. the tension in the cable is greater than mg because there has to be a net upward force. Submit Previous Answers Correct The ball is moving in a circle. Any object moving in a circle has a centripetal acceleration pointing toward the center of the circle. There must be a net force pointing toward the center to cause the centripetal acceleration. The center of the circle is above the ball, so there must be a net force pointing upward. There can also be a tangential acceleration if the object is speeding up or slowing down, but the tangential acceleration is zero at the lowest point where the changes from speeding up to slowing down. Part B What is the tension in the cable when the ball is at its lowest point? Express your answer with the appropriate units. View Available Hint(s) HA ? T = Value Units Submit Request Answer