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2 years ago

Explain why your PE and KE are usually not both high at the same time (If PE is high then usually KE is low)

1 answer:

4 0

Might help:

an object can have both kinetic and potential energy at the same time. for example, an object which is falling, but has not reached the ground has kinetic energy because it is moving downwards, and potential energy because it is able to move downwards even further than it already has. as an object falls its potential energy decreases, while its kinetic energy increases. the decrease in potential energy is exactly equal to the increase in kinetic energy.

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A weight lifter lifts a dumbbell a certain height in 2.0 s, while a competitor does the same workin 1.0 s. Compared to the power

Aloiza [94]

Answer:

a. one-half as great

Explanation:

The power developed by the first lifter is one-half as great as that of the second person.

Power is defined as the rate at which work is done;

Power = $\frac{workdone}{time}$

Since the two lifters do the same work at different time, let us estimate their power;

P₁ = $\frac{workdone}{2}$ P₂ = $\frac{workdone }{1}$

We see that for P₁, power is half of the work done whereas in P₂ power is the same as the work done.

Therefore,

The power of the first weight lifter is one-half the second lifter.

4 0

3 years ago

Say that you are in a large room at temperature TC = 300 K. Someone gives you a pot of hot soup at a temperature of TH = 340 K.

DiKsa [7]

Answer:0.061

Explanation:

Given

$T_C=300 k$

Temperature of soup $T_H=340 K$

heat capacity of soup $c_v=33 J/K$

Here Temperature of soup is constantly decreasing

suppose T is the temperature of soup at any instant

efficiency is given by

$\eta =\frac{dW}{Q}=1-\frac{T_C}{T}$

$dW=Q(1-\frac{T_C}{T})$

$dW=c_v(1-\frac{T_C}{T})dT$

integrating From $T_H$ to $T_C$

$\int dW=\int_{T_C}^{T_H}c_v(1-\frac{T_C}{T})dT$

$W=\int_{T_C}^{T_H}33\cdot (1-\frac{300}{T})dT$

$W=c_v\left [ T-T_C\ln T\right ]_{T_H}^{T_C}$

$W=c_v\left [ \left ( T_C-T_H\right )-T_C\left ( \ln \frac{T_C}{T_H}\right )\right ]$

Now heat lost by soup is given by

$Q=c_v(T_C-T_H)$

Fraction of the total heat that is lost by the soup can be turned is given by

$=\frac{W}{Q}$

$=\frac{c_v\left [ \left ( T_C-T_H\right )-T_C\left ( \ln \frac{T_C}{T_H}\right )\right ]}{c_v(T_C-T_H)}$

$=\frac{T_C-T_H-T_C\ln (\frac{T_C}{T_H})}{T_C-T_H}$

$=\frac{300-340-300\ln (\frac{300}{340})}{300-340}$

$=\frac{-40+37.548}{-40}$

$=0.061$

4 0

3 years ago

What is the rock cycle and how does it change the lithosphere?

Ira Lisetskai [31]

The rock cycle is a basic concept in geology that describes the time-consuming transitions through geologic time among the three main rock types: sedimentary, metamorphic, and igneous. As the adjacent diagram illustrates, each of the types of rocks is altered or destroyed when it is forced out of its equilibrium conditions. An igneous rock such as basalt may break down and dissolve when exposed to the atmosphere, or melt as it is subducted under a continent. Due to the driving forces of the rock cycle, plate tectonics and the water cycle, rocks do not remain in equilibrium and are forced to change as they encounter new environments. The rock cycle is an illustration that explains how the three rock types are related to each other, and how processes change from one type to another over time. This cyclical aspect makes rock change a geologic cycle and, on planets containing life, a biogeochemical cycle.

Plate movements drive the rock cycle by pushing rocks back into the mantle, where they melt and become magna again. Plate movements also cause the folding, faulting and uplift of the crust that move rocks through the rock cycle.

sources: wikapedia, Harmonybaddie on brainly

8 0

3 years ago

An electron is a particle with a ____.

Dahasolnce [82]

A beta particle. Hoped I help. Sorry if it wrong.

4 0

3 years ago

Read 2 more answers

A machinist is required to manufacture a circular metal disk with area 1900 cm2. (a) What radius produces such a disk? (Round yo

alexgriva [62]

Answer:

24.5987 cm

Explanation:

A = 1900 cm^2

Let r be the radius of disc.

The area of disc is given by

A = π r²

Where, π = 31.4

1900 = 3.14 x r²

r² = 605.095

r = 24.5987 cm

6 0

3 years ago