Answer: Net capital outflow is determined by the real interest rate, not the real exchange rate
Step-by-step explanation:
In the foreign-currency market, the supply of dollars is not dependent on the real exchange rate and so the supply curve will be vertical to indicate this independence by showing inelasticity which means that it is unaffected by the variables in the foreign-currency market.
Supply of dollars is rather dependent on the real interest rate.
This is because dollars get into the world economy (supply of dollars) as a result of investments by Americans into markets abroad in the form of Net Capital Outflow. If American real interest rate is low, Americans will invest in other countries with a higher rate of return thereby pumping more dollars into the world economy.