False not radioactive isotope will have a half-life
Answer:
t = 6.09 seconds
Explanation:
Given that,
Speed, v = 44.1 cm/s
Distance, d = 269 cm
We need to find the time interval of the marble. Speed is distance per unit time.

Hence, the time interval of the marble is 6.09 seconds.
Kinetic energy= 1/2 m v^2
so... 1/2(1350)(12^2)
kinetic energy = 97200Joules