An electric heater rated 2.0kW is used to heat 15g of water in a kettle. The initial temperature of the water is 20°C. What time does it take to heat the water to it's boiling point.

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be

your answer is c! hope this : )