Answer: K =24 psi
Explanation:
Given: Standard deviation =3psi
Internal pressure strength =157psi
Number of random bottle =n=64
K= 3 × square root of 64
K= 3×8=24 psi
If mean internal pressure K fall below K,
157-1.3=155.7psi
At 2%:
0.16×64 = 10.24
Here in all such collision type question we can use momentum conservation as we can see that there is no external force on this system

as we know that




now from above equation we have



so the speed of combined system is 2 m/s
-- It takes the brick 8.9 seconds to reach the ground.
-- At the instant of the "splat", it's falling at 89 m/s.
-- The mass doesn't matter. If not for air resistance, every object
would fall at the same rate. The answer is the same for a feather,
a rubber chicken, a brick, or a school bus.
B is you answer sorry i dont quite know how to explain it in a way that you and anybody else would understand it.