Answer:
a)  y= 3.5 10³ m, b)   t = 64 s
Explanation:
a) For this exercise we use the vertical launch kinematics equation
Stage 1
           y₁ = y₀ + v₀ t + ½ a t²
           y₁ = 0 + 0 + ½ a₁ t²
Let's calculate
          y₁ = ½ 16 10²
          y₁ = 800 m
At the end of this stage it has a speed
         v₁ = vo + a₁ t₁
         v₁ = 0 + 16 10
         v₁ = 160 m / s
Stage 2
         y₂ = y₁ + v₁ (t-t₀) + ½ a₂ (t-t₀)²
         y₂ = 800 + 150 5 + ½ 11 5²
         y₂ = 1092.5 m
Speed is
         v₂ = v₁ + a₂ t
         v₂ = 160 + 11 5
         v₂ = 215 m / s
The rocket continues to follow until the speed reaches zero (v₃ = 0)
          v₃² = v₂² - 2 g y₃
          0 = v₂² - 2g y₃
          y₃ = v₂² / 2g
          y₃ = 215²/2 9.8
          y₃ = 2358.4 m
The total height is
           y = y₃ + y₂
           y = 2358.4 + 1092.5
           y = 3450.9 m
            y= 3.5 10³ m
b) Flight time is the time to go up plus the time to go down
Let's look for the time of stage 3
           v₃ = v₂ - g t₃
           v₃ = 0
           t₃ = v₂ / g
           t₃ = 215 / 9.8
           t₃ = 21.94 s
The time to climb is
            = t₁ + t₂ + t₃
 = t₁ + t₂ + t₃
           t_{s} = 10+ 5+ 21.94
           t_{s} = 36.94 s
The time to descend from the maximum height is
           y = v₀ t - ½ g t²
When it starts to slow down it's zero
          y = - ½ g t_{b}²
          t_{b}  = √-2y / g
          
         t_{b} = √(- 2 (-3450.9) /9.8)
         t_{b} = 26.54 s
Flight time is the rise time plus the descent date
         t = t_{s} + t_{b}
         t = 36.94 + 26.54
         t =63.84 s
         t = 64 s
 
        
             
        
        
        
Answer:
0.15625 grams
Explanation:
Half life: It is related to the decay of radioactive material. The duration in which  half of the material will be degraded/decayed. That means after half life 50% of the radioactive material will be left. Here the half life is 28 years.
Initial quantity of the sample: 2.5 grams.
After 28 years, the leftover quantity = 1.25 grams
After 56 years, the leftover quantity = 0.625 grams
After 84 Years, the leftover quantity = 0.3125 grams
After 112 years, the leftover quantity = 0.15625 grams
 
        
             
        
        
        
Answer:
2. ( b ) zero
3. ( c ) 10 s
4. Uniform then decreasing
Explanation:
2. 
Since the motion is uniform, initial and final velocity will be 0, hence acceleration will be zero.
3.
Initial velocity ( u ) = 5 m/s
Final velocity ( v ) = 35 m/s
Acceleration ( a ) 3 m/s^2
To find : Time ( t )
Formula : -
t = v - u / a
  = 35 - 5 / 3
  = 30 / 3
t = 10 s
 
        
                    
             
        
        
        
Answer: All isotopes of a given element have the same number of protons but different numbers of neutrons in each atom. ... Each atomic number identifies a specific element, but not the isotope; an atom of a given element may have a wide range in its number of neutrons.
Explanation: Hopefully this helps. Have a great day.