If the activity of a radioactive substance is initially 396 disintegrations/min and two days later it is 281 disintegrations/min, what is the activity four days later still, or six days after the start? Give your answer in disintegrations/min.

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

read more on -

where is the photo and the answer choices?

magnets not strong enough

explanation: