Which condition will cause the pressure exerted by a gas in a closed container to increase?
1 answer:
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Answer:
D.
Explanation:
In order to know how long after Bill released his rock should Ted throw his if they want the stones to hit the water simultanously, we need to calculate the time needed to hit the water to both rocks independent each other, and just take the difference.
For the rock dropped by Bill, as the only influence on it is gravity (accelerating it downwards with an acceleration equal to g), and v₀ =0, we can use the following kinematic equation:
where y = height = 40 ft.
As all the parameters are given in SI units, it is advisable to convert this value to m, as follows:
Now, we can solve for t, as follows:
For the rock thrown down at 10 m/s, the kinematic equation we just have used becomes:
This leaves us a quadratic equation on t, as follows:
Taking the positive root, we have:
t = -1.02 s + 1.88 s = 0.86 s
So, in order to get that both rocks hit the water at the same time, Ted will need to wait the difference between both times:
Δt = 0.86 s - 1.58s = -0.72 s
Answer:
b) √[(kx²/m) - 2gx]
Explanation:
The energy at the lowest point is equal to:
where:
Eelas = elastic energy [J]
k = spring constant [N/m]
x = extension of the spring [m]
We consider the lowest point, as the point where the potential energy is zero. At the moment when the person goes back through the point of the normal length of the elastic cord, it is this point that the person will have potential energy and kinetic energy.