As your hand moves back and forth to generate longitudinal pulses in a spiral spring, your

You go rock climbing with a pack that weighs 70 N and you reach a height of 30 m. how much work did you do to lift your pack? If

Vikentia [17]

When you climb, earth exerts gravitational force on pack in downward direction(pointing towards the center of earth).
In order to climb, you need to work against work done by gravity on the pack.
Hence work done by you = work done by gravity on pack
= Force x displacement = 70 x 30 = 2100 J.

So you need to do 2100 joules of work to lift your pack.

Power is the rate of work done.
Therefore power = work done by you/time(in seconds)
= 2100/600 =3.5 watts

8 0

3 years ago

One end of an insulated metal rod is maintained at 100 ∘C and the other end is maintained at 0.00 ∘C by an ice–water mixture. Th

lozanna [386]

Answer:

$k=105.0359\times 10^4\,W.m^{-1}.K^{-1}$

Explanation:

Given:

temperature at the hotter end, $T_H=100^{\circ}C$

temperature at the cooler end, $T_C=0^{\circ}C$

length of rod through which the heat travels, $dx=0.7\,m$

cross-sectional area of rod, $A=1.1\times 10^{-4}\,cm^2$

mass of ice melted at zero degree Celsius, $m=8.7\times 10^{-3}\,kg$

time taken for the melting of ice, $t=15\times60=900\,s$

thermal conductivity k=?

By Fourier's Law of conduction we have:

$\dot{Q}=k.A.\frac{dT}{dx}$ ......................................(1)

where:

$\dot{Q}$ =rate of heat transfer

dT= temperature difference across the length dx

Now, we need the total heat transfer according to the condition:

we know the latent heat of fusion of ice, $L = 334000\,J.kg^{-1}$

$Q=m.L$

$Q=8.7\times 10^{-3}\times 334000$

$Q=2905.8\,J$

Now the heat rate:

$\dot{Q}=\frac{Q}{t}$

$\dot{Q}=\frac{2905.8}{900}$

$\dot{Q}=3.2287\,W$

Now using eq,(1)

$3.2287=k\times 1.1\times 10^{-4} \times \frac{100}{0.7}$

$k=205.4606\,W.m^{-1}.K^{-1}$

8 0

3 years ago

The singing of an opera singer caused a drinking glass to shatter. Explain this using what you know about resonance.

rusak2 [61]

Explanation:

Resonance: Resonance is the phenomenon which occurs when the applied frequency on the object is equal to its natural frequency.

In the given problem, the singing of an opera singer caused a drinking glass to shatter.

This occurs due to the phenomenon resonance. The applied frequency of the singing of an opera singer on the drinking glass matches with the natural frequency of the drinking glass. It causes a glass to shatter.

5 0

3 years ago

Read 2 more answers

Can some one give me a conclusion for natural resources

levacccp [35]

Answer:

The exploitation of high-value natural resources—oil, gas, minerals, and timber—has often been a key factor in triggering, escalating, or sustaining violent conflicts around the globe. Competition over renewable resources such as land and water is on the rise, and environmental degradation, population growth, and climate change are compounding the challenges. Governments are therefore under increasing pressure to sustainably manage natural resources and resolve conflicts around their ownership, management, allocation, and control.

8 0

3 years ago

A tiger runs one kilometer. The tiger does 15,000 J of work and has a total power output of 500 W. How many minutes does it take

defon

Power is the amount of energy consumed per unit time. Having no direction, it is a scalar quantity. As is implied by the equation for power, a unit of power is equivalent to a unit of work divided by a unit of time. The formula would be as follows:

P = W/t

We calculate as follows:

500 W = 15000 J / t
t = 30 s

3 0

3 years ago