Answer:
80%
Explanation:
Efficiency of machine = work output/work input ×100 %
From question, work output = 20J
Work input = 25J.
Therefore efficiency = 20/25 × 100 %
Efficiency = 20×4 %
Efficiency = 80%
I hope this was helpful, please mark as brainliest
Answer:
1694 days
Explanation:
In first-order kinetics, the rate is proportional to the amount.
dA/dt = kA
For first-order kinetics, the rate k can be found using the half-life:
t₁,₂ = (ln 2) / k
In other words, the half-life is inversely proportional with the rate.
At the lower temperature, the rate is reduced to a third, so the half-life increases by a factor of 3. Meaning that the new half-life is 170 × 3 = 510 days.
The "shelf life" is the time it takes to reduce the initial amount to 10%. We can solve for this using the half-life equation.
A = A₀ (½)^(t / t₁,₂)
A₀/10 = A₀ (½)^(t / 510)
1/10 = (½)^(t / 510)
ln(1/10) = (t / 510) ln(½)
ln(10) = (t / 510) ln(2)
ln(10) / ln(2) = t / 510
t = 510 ln(10) / ln(2)
t ≈ 1694
Answer:
Pretty sure magnetic waves thank me later bro bro
