Aradioactive isotope has a half-life of 3 hours. if a scientist has 30 grams of the isotope, how much is left after 15 hours

what is the average time it took the car to travel 0.25 meters?

⇒ 2.23 seconds

what is the average time it took the car to travel 0.50 meters?

⇒ 3.13 seconds

the answer is 0.42 is that is an option. this question provides no info

answerspecific gravity;

weight of any object is given by

w = m*g

where m is mass of the object and g is the acceleration due to gravity.

for earth the value of g is 9.8 m/s^2 so

w=117.6 n m=12 g=?

117.6=12g => g=9.8 m/s^2

which is the force of gravity on earth.