Final answer:
The mass of the door closing at 0.2m/s with a kinetic energy of 1.6J is 16 kg.
Step-by-step explanation:
In order to calculate the mass of the door, we can use the equation for kinetic energy:
KE = (1/2)mv^2
Given that the kinetic energy of the door is 1.6 J and its velocity is 0.2 m/s, we can rearrange the equation to solve for the mass:
m = (2KE) / v^2
Plugging in the values, we get:
m = (2 * 1.6 J) / (0.2 m/s)^2
m = 16 kg
Therefore, the mass of the door is 16 kg.