3.6 kg.
<h3>Explanation</h3>
How much heat does the hot steel tool release?
This value is the same as the amount of heat that the 15 liters of water has absorbed.
Temperature change of water:
.
Volume of water:
.
Mass of water:
.
Amount of heat that the 15 L water absorbed:
.
What's the mass of the hot steel tool?
The specific heat of carbon steel is
.
The amount of heat that the tool has lost is the same as the amount of heat the 15 L of water absorbed. In other words,
.
.
.
Each vegetables and fruits will have different response to the varying temperature and atmospheric condition of the surrounding. Some may become rotten in a shorter period of time. In this regard the price would get lower in order for the goods to get sold easily.
I would make the ramp flatter. In doing so the ramp would have to be longer.
Answer:

Explanation:
Given:
height above which the rock is thrown up, 
initial velocity of projection, 
let the gravity on the other planet be g'
The time taken by the rock to reach the top height on the exoplanet:
where:
final velocity at the top height = 0 
(-ve sign to indicate that acceleration acts opposite to the velocity)

The time taken by the rock to reach the top height on the earth:



Height reached by the rock above the point of throwing on the exoplanet:

where:
final velocity at the top height = 0 


Height reached by the rock above the point of throwing on the earth:



The time taken by the rock to fall from the highest point to the ground on the exoplanet:
(during falling it falls below the cliff)
here:
initial velocity= 0 



Similarly on earth:

Now the required time difference:


smaller, because the part of the velocities cancel each other out