Answer:
t₁ = 3 s
Explanation:
In this exercise, the vertical displacement equation is not given
y = 240 t + 16 t²
Where y is the displacement, 240 is the initial velocity and 16 is half the value of the acceleration
Let's replace
864 = 240 t + 16 t²
Let's solve the second degree equation
16 t² + 240 t - 864 = 0
Let's divide by 16
t² + 15 t - 54 = 0
The solution of this equation is
t = [-15 ± √(15 2 - 4 1 (-54)) ] / 2 1
t = [-15 ±√(225 +216)] / 2
t = [-15 + - 21] / 2
We have two solutions.
t₁ = [-15 +21] / 2
t₁ = 3 s
t₂ = -18 s
Since time cannot have negative values, the correct t₁ = 3s
B. Fusion requires very high pressure and temperature.
Explanation:
Nuclear fusion is the combination of atomic nuclei into larger ones with the release of a large amount of energy.
Nuclear fission is the decay process in which a heavy nuclide is bombarded with with neutrons.
- Both processes release a huge amount of energy.
- But fusion produces far more energy.
- The reason why nuclear fusion is not in use is because of the high pressure and temperature needed start it.
- The activation energy is high and the energy barrier is very great.
- Only the core of the sun naturally favors fusion
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Answer
given,
tourist travels = 1500 miles
second plane averages 50 miles per hour faster than the first plane.
x = y + 50
The tourist uses the slower plane for the first 500 and the faster plane for the next 1000 miles.
total flying time = 6.5 hours





on solving equation
y = 86.67 mile/hr
x = 86.67 + 50
x = 136.67 mile/hr
Answer:

Explanation:
density of the solid box material = 
density of the liquid material = 
Given that
solid box floats with two thirds of its volume submerged in a liquid
let V be the volume of the box
then,

⇒
so, the ratio of densities of solid and and the liquid is 2/3