Though the question does not ask for anything, I'll assume you need to calculate the speed of the lift.
Answer:
The lift travels at 1.4 m/s
Explanation:
Kinetic Energy
Is the type of energy of an object due to its state of motion. It's proportional to the square of the speed and the mass.
The equation for the kinetic energy is:
[tex]\displaystyle K=\frac{1}{2}mv^2[/tex]
Where:
m = mass of the object
v = speed at which the object moves
The kinetic energy is usually expressed in Joules (J)
If we already know the value of the kinetic energy, we can find the speed by solving for v:
[tex]\displaystyle v=\sqrt{\frac{2K}{m}}[/tex]
The lift has a mass of m=4200 Kg and has a kinetic energy of K=4116 J, thus it's moving at a speed of:
[tex]\displaystyle v=\sqrt{\frac{2*4116}{4200}}[/tex]
[tex]\displaystyle v=\sqrt{1.96}[/tex]
v = 1.4 m/s
The lift travels at 1.4 m/s