An old building is being demolished by swinging a heavy metal ball from a crane. Suppose that such a 115kg ball swings from a 20-m-long wire at speed 12m/s as the wire passes the vertical orientation.

a) What tension force must the wire be able to withstand in order not to break?

b)Assume the ball stops after sinking 1.5 m into the wall. What was the average force that the ball exerted on the wall?

Under conditions for which the same room temperature is maintained by a heating or cooling system, it is not uncommon for a person to feel chilled in the winter but comfortable in the summer. provide a plausible explanation for this situation (with supporting calculations) by considering a room whose air temperature is maintained at 20â°c throughout the year, while the walls of the room are nominally at 27â°c and 14â°c in the summer and winter, respectively. the exposed surface of a person in the room may be assumed to be at a temperature of 32â°c throughout the year and to have an emissivity of 0.90. the coefficient associated with heat transfer by natural convection between the person and the room air is approximately 2 w/m2 â‹…â‹… k. what is the ratio of the thermal resistance due to convection to the thermal resistance due to radiation in the summer? what is the ratio of thermal resistances in the winter

This energy transformation diagram represents the energy of a skateboarder moving along a half-pipe. as she skates toward the top of the half-pipe, her original kinetic energy is converted to potential energy and friction. how much of the energy is potential?

How do you count the total number of atoms present on one side of a chemical equation?