The graph below shows time versus temperature for water in a tank after the heater has been switched on. The heater is switched off at A on the graph. (A) The mass of water in the tank is 50kg. What is the amount of heat supplied by the heating coil in the first 20 minutes?

You have been hired to design a spring-launched roller coaster thatwill carry two passengers per car. the car goes up a 10-m highhill, then descends 15m to the track's lowest point. you'vedetermined that the spring can be compressed a maximum o 2.0m andthat a loaded car will have a maximum mass of 400kg. for safetyreasons, the spring constant should be 10% larger than the minimumneeded for the car to just make it over the top. a) what spring constant (k) should you specify ? b) what is the maximum speed of a 350 kg car if the spring iscompressed the full amount.