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3 years ago

Please help if you can.

1 answer:

3 0

Initially there were 10 bulbs of 60 Watt power

So total power of all bulbs = 60 * 10 = 600 W

now each bulb used for 4 hours daily

so total energy consumed daily

$E = P * t$

$E = 600 * 4 = 2400 Wh$

$E = 2.4 kWh$

now we have total power consumed in 1 year

$E = 365 * 2.4 = 876 kWh$

cost of electricity = 10 cents/ kWh

so total cost of energy for one year

$P_1 = 876 * 10 = 8760 cents = $87.60$

Now if all 60 Watt bulbs are replaced by 30 Watt bulbs

So total power of all bulbs = 30 * 10 = 300 W

now each bulb used for 4 hours daily

so total energy consumed daily

$E = P * t$

$E = 300 * 4 = 1200 Wh$

$E = 1.2 kWh$

now we have total power consumed in 1 year

$E = 365 * 1.2 = 438 kWh$

cost of electricity = 10 cents/ kWh

so total cost of energy for one year

$P_1 = 438 * 10 = 4380 cents = $43.80$

total money saved in 1 year

$Savings = 87.6 - 43.8 = $43.80$

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lilavasa [31]

Answer:

D/H =15

Explanation:

We can find first the peak height H, taking into consideration, that at the maximum height, the ball will reach momentarily to a stop.
At this point, we can find the value of H, applying the following kinematic equation:

$v_{f} ^{2} -v_{0} ^{2} = 2* g* H (1)$

If vf=0, if we assume that the positive direction is upwards, we can find the value of H as follows:

$H = \frac{v_{0} ^{2} }{2*g} (2)$

$v_{f} ^{2} -v_{1} ^{2} = 2* g* D (3)$

In order to find v₁, we can use the same kinematic equation that we used to get H, but now, we know that v₀ = 0.
When we replace these values in (1), we find that v₁ = -v₀.
Replacing in (3), we have:

$(4*v_{0})^{2} - (-v_{0}) ^{2} = 2* g* D\\ \\ 15*v_{0}^{2} = 2*g*D$