Q. After a tornado, a 0.55-g straw was found embedded 2.6 cm into the trunk of a tree. If the average force exerted on the straw by the tree was 70 N, what was the speed of the straw when it hit the tree?
Q. A small electric immersion heater is used to heat 78 g of water for a cup of instant coffee. The heater is labeled "120 watts" (it converts electrical energy to thermal energy at this rate). Calculate the time required to bring all this water from 20°C to 100°C, ignoring any heat losses. (The specific heat of water is 4186 J/kg·K.)