Answer:
The kinetic energy is 16 joules.
Step-by-step explanation:
Kinetic energy (E) is given by:

Where:
m: is the mass
v: is the speed
When the kinetic energy is 4 joules, the speed of the object is:
Now, if the speed is increased twice then we have:
![E_(2) = (1)/(2)mv_(2)^(2) = (1)/(2)m(2v_(1))^(2) = (1)/(2)m[4((8)/(m))] = 16 J](https://img.qammunity.org/2022/formulas/physics/high-school/xwwli5a3jsbur9ydqk27fqlwk0mv0tl5aj.png)
Therefore, the kinetic energy is 4 times the initial value.
I hope it helps you!