Calculate the amount of energy produced in joules by 100- watt light bulb lit for 2.5 hours.

a.Calculate the average speed (in km/h) of Charlie, who runs to the store 4 kilometers away in 30 minutes. b.Calculate the dista

sveta [45]

as per the question charlie runs to the store which is 4 km away

hence the total distance covered [S] is 4 km

he takes 30 minutes to reach the store.

hence the total time taken [t] = 30 minutes=0.5 hour

We have to calculate the average speed.

the average speed[v]= $=\frac{S}{t}$

= $\frac{4 km}{0.5 hour}$

=8 km/hour

then we have to calculate the total distance traveled by charlie in 1 hour.

the distance covered S= $V_{avg} *t$

=8 km/hour ×1 hour

=8 km

Hence the average speed of charlie is 8 km/hour and he covers a distance of 8 km in 1 hour.

7 0

3 years ago

How quickly a leaf grows is proportional how big [ie the surface area] the leaf is. If the area of the leaf grows from 2cm2 to 3

marusya05 [52]

Answer: 9 days

Explanation:

Step 1

Let the rate of Leaf growth r be defined as, $\frac{Increase in area}{time taken}$ = $\frac{A1 - A}{t}$

where A is initial area of the leaf, A1 is the final area of the leaf and t is the time taken for the increase in Area.

Express the proportional relationship in equation.

Given that rate of leaf growth, r is proportional to the surface area of the leaf A. we have r ∝ A.

r = kA, where k is the rate constant.

therefore, k = $\frac{r}{A}$

when A = 2 $cm^{2}$ , A1 = 3

so k = $\frac{\frac{3 - 2}{3}}{2}$

= $\frac{1}{3}$ ÷ 2

= 0.33 ÷ 2

k = 0.167

After calculating the rate constant k, we then find the time t when A1 is 5 $cm^{2}$

we have r = k × A1 = $\frac{A1 - A}{t}$

so, 0.167 × 2 = $\frac{5 - 2}{t}$

0.33 = $\frac{3}{t}$ .

t = 3/0.33

Therefore, t = 9 days.

3 0

3 years ago

The compound PCl5 decomposes into Cl2 and PCl3. The equilibrium of PCl5(g) Cl2(g) + PCl3(g) has a Keq of 2.24 x 10-2 at 327°C. W

nordsb [41]

Take note of the reaction formula which is PCl5=Cl2+PCl3.
The Keq = [Cl2] * [PCl3] / [PCl5]=2.24*10^-2.
For the reason that the volume is 1 liter, the concentration of Cl2 will be computed through: (2.24 * 10^-2) * 0.235 / 0.174 = 0.0303 mol/L is the answer.

7 0

2 years ago

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25 POINTS

Alexandra [31]

pshyical change is a usually reversible change of a substance, as size or shape: Freezing a liquid is a physical change. Compare chemical change.

internal change is when the movement of the particles increases

specific latent heat is the amount of energy per kg (unit mass) required to change ice to water without change in temperature.

4 0

3 years ago

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In a simple machine, the energy input is 120 J. If the efficiency of the machine is 80%, calculate the energy output

pashok25 [27]

Answer:

<h2>96 Joules</h2>

Explanation:

We know that efficiency is the ratio of output power by input power. i.e. Efficiency describes the quality of machine or system how good it is.