Answer:
B) t = 1.83 [s]
A) y = 16.51 [m]
Explanation:
To solve this problem we must use the following equation of kinematics.

where:
Vf = final velocity = 0
Vo = initial velocity = 18 [m/s]
g = gravity acceleration = 9.81 [m/s²]
t = time [s]
Note: the negative sign in the above equation means that the acceleration of gravity is acting in the opposite direction to the motion.
A) The maximum height is reached when the final velocity of the ball is zero.
0 = 18 - (9.81*t)
9.81*t = 18
t = 18/9.81
t = 1.83 [s], we found the answer for B.
Now using the following equation.

where:
y = elevation [m]
Yo = initial elevation = 0
y = 18*(1.83) - 0.5*9.81*(1.83)²
y = 16.51 [m]
The sample appears to have gone through 3 half-lives
1st half life: 1000 to 500 g
2nd half life: 500 to 250 g
3rd half life: 250 to 125 g
The duration of a half-life, therefore, can be inferred to be 66 ÷ (3) = 22 days.
After a 4th half life, there will be 125÷2= 62.5 g.
At this point, an additional 22 days will have passed, for a total of 88 days.
Answer is C.
Answer:
α= 1.3 10-5 ºC⁻¹
Explanation:
La dilatación termica de los cuerpos esta dada por la relación
ΔL = L₀ α ( T -T₀)
en este caso nos piden el coeficiente de dilatación térmica
α =DL/L₀ DT
calculemos
α = ( 100,13 -100)/[100 (100 – 0)]
α = 1,3 10-5 ºC⁻¹
Traduction
The thermal expansion of bodies is given by the relationship
ΔL = L₀ α (T -T₀)
in this case they ask us for the coefficient of thermal expansion
α = ΔL / L₀ ΔT
let's calculate
α = (100,13 -100) / [100 (100 - 0)]
α= 1.3 10-5 ºC⁻¹