1. A 1,000. kg car with a speed of 90.0 km/h brakes to a stop. How many calories of heat are generated by the brakes as a result?
2. A 50.0 g silver spoon at 20.0 °C is placed in a cup of coffee at 90.0 °C. How much heat does the spoon absorb from the coffee to reach a temperature of 89.0 °C?
3. A 1.00 kg block of ice at 0 °C is added to a picnic cooler. How much heat will the ice remove as its melts to water at 0 °C?
4. A heat engine converts 100.0 cal from a supply of 400.0 cal into work. How much mechanical work was done?