Is a iron a conduction , raidition or convection

Agirl throws a ball. if the ball's acceleration is 12 m/sec/sec and its mass is 0.5 kg, how much force did the girl apply to the ball?

Acircuit contain a 5-ohm,a3-ohm,and an 8-ohm resistor in series. what is the total resistance of the circuit ?

The lid of a pressure cooker forms a nearly airtight seal. steam builds up pressure and increases temperature within the pressure cooker so that food cooks faster than it does in an ordinary pot. the system is defined as the pressure cooker and the water and steam within it. if 2.0 g of water is sealed in a pressure cooker and then vaporized by heating, and 5127 j must be added as heat to completely vaporize the water, what is the change in the system’s internal energy? answer in units of j.