Here if we assume that there is no air friction on both balls then we can say

now the acceleration is given as


so here both the balls will have same acceleration irrespective of size and mass
so we can say that to find out the time of fall of ball we can use


now from above equation we can say that time taken to hit the ground will be same for both balls and it is irrespective of its mass and size
Answer:
The smallest part of a millimeter that can be read with a digital caliper with a four digit display is 0.02mm. Thus, it has to be converted to centimetre. So, divide by 10, we then have 0.02/10= *0.002cm* not mm.
B) atmosphere pressure, i believe
Given:
u(initial velocity)=0
v(final velocity)= 10 m/s
t= 4 sec
Now we know that
v= u + at
Where v is the final velocity
u is the initial velocity
a is the acceleration measured in m/s^2
t is the time measured in sec
10=0+ax4
a=10/4
a=2.5 m/s^2
I believe the answer is elements!!!!