Check and analyze condition of foot nails​

Spend time observing or thinking about events that involve matter and energy. which events can you explain? which events can’t you explain?

An object moves from the position +34m to the position -15m in 15 seconds. what is it's total displacement? what is it's average velocity?

An ice-making machine inside a refrigerator operates in a carnot cycle. it takes heat from liquid water at 0.0 degrees celsius and rejects heat to a room at a temperature of 19.2 degrees celsius. suppose that liquid water with a mass of 76.3kg at 0.0 degrees celsius is converted to ice at the same temperature. take the heat of fusion for water to be l_f = 3.34*10^5 j/kg.how much energy e must be supplied to the device? express your answer in joules.