20N•m or 20J. Work is equal to force•distance, and 5N•4m is 20N•m, or J
Here it is given that initial speed of the package will be same as speed of the helicopter

displacement of the package as it is dropped on ground

acceleration is due to gravity

now by kinematics



by solving above equation we have

so it will take 5.2 s to reach the ground
Sodium (Na) is a Alkali metal so that's the answer
We can use the law of conservation of energy to solve the problem.
The total mechanical energy of the system at any moment of the motion is:

where U is the potential energy and K the kinetic energy.
At the beginning of the motion, the ball starts from the ground so its altitude is h=0 and therefore its potential energy U is zero. So, the mechanical energy is just kinetic energy:

When the ball reaches the maximum altitude of its flight, it starts to go down again, so its speed at that moment is zero: v=0. So, its kinetic energy at the top is zero. So the total mechanical energy is just potential energy:

But the mechanical energy must be conserved, Ef=Ei, so we have

and so, the potential energy at the top of the flight is
Show me the graphs and i would be glad to help u