All categories

3 years ago

Which is the best description of power? A. the amount of kinetic energy lost during motion

Engineering

1 answer:

cestrela7 [59]3 years ago

6 0

Answer:

D. a measure of how fast a machine performs work

Explanation:

Power can be defined as the energy required to do work per unit time.

Mathematically, it is given by the formula;

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

Hence, the best description of power is that, it is a measure of how fast a machine performs work.

This can be calculated by using the mathematical expression below;

$Power = \frac {Work done}{Time}$

But we know that, $Workdone = force * distance$

You might be interested in

3. A particle is projected to the right from the position S = 0, when an initial velocity of 8 m/s. If the acceleration of the p

Alenkasestr [34]

Answer:

a) 3.5 m

b) 14 secs

c) 1.4 secs

Explanation:

a) Determine the distance the particle will travel

given velocity ( final velocity ) = 5 m/s

v^2 = u^2 + 2as

s = ( v^2 - u^2 ) / 2a

= ( 5^2 - 8^2 ) / 2 ( -0.5 * 5^3/2 )

= 3.5 m

b) Determine the time when v = 1m/s

V = u + at

1 = 8 + ( -0.5 * 1^3/2 ) * t

∴ t = 14 secs

c) Determine the time required for particle to travel 8 m

we will employ both equations above

V^2 = u^2 + 2as

s = 8 m , V = unknown , u = 8 m/s back to equation

V^2 = 8^2 + 2 ( - 1/2 * V^3/2 ) * 8

∴ V^2 + 8V^3/2 - 64 = 0

resolving the above equation

V = 3.478 m/s

now using the second equation

V = u + at

3.478 = 8 + ( - 1/2 * 3.478^3/2 ) * t

hence : t = 1.4 secs

6 0

3 years ago

The car travels around the portion of a circular track having a radius of r = 500 ft such that when it is at point A it has a ve

stellarik [79]

Answer:

Explanation:

Given

velocity at A is $v=4\ ft/s$

For $r=500\ ft$

velocity is increasing at $\dot{v}=0.004t\ ft/s^2$

Tangential acceleration is given by

$a_t=\frac{\mathrm{d} v}{\mathrm{d} t}$

$a_t=0.004t=\frac{\mathrm{d} v}{\mathrm{d} t}$

$\int 0.004tdt=\int dv$

$\int dv=\int 0.004tdt$

$v=0.002t^2+c$

at $t=0\ v=4\ ft/s$

$4=0.002\cdot 0+c$

$c=4\ ft/s$

thus $v=0.002t^2+4$

Velocity in terms of Displacement is given by

$v=\frac{\mathrm{d} s}{\mathrm{d} t}$

$\Rightarrow \int ds=\int \left ( 0.002t^2+4\right )dt$

$\Rightarrow s=\frac{0.002t^3}{3}+4t$

When car has traveled $\frac{3}{4}$ th of distance i.e.

$s=\frac{3}{4}\times (2\pi r)=\frac{3\pi r}{2}$

$s=750\pi$

$750\pi =\frac{0.002t^3}{3}+4t$

$\Rightarrow \frac{0.002t^3}{3}+4t-2356.5=0$

on solving we get $t=139.23\ s$

Thus velocity at $t=139.23\ s$

$v=42.76\ s$

(b)Acceleration when car has traveled three-fourth the way of track

normal acceleration $a_n=\frac{v^2}{r}=\frac{(42.76)^2}{500}$

$a_n=3.658\ m/s^2$

Tangential acceleration $a_t at t=139.23\ s$

$a_t=0.556\ m/s^2$

Net acceleration $a_t=\sqrt{(a_n)^2+(a_t)^2}$

$a_n=\sqrt{(3.658)^2+(0.556)^2}$

$a_n=3.7\ m/s^2$

8 0

3 years ago

Imagine you work for the public housing agency of a city, and you have been charged with keeping track of who is living in the a

SOVA2 [1]

In this question, we are missing some of the information that is necessary in order to answer this question properly. However, we can look at what a relational database is in order to help you answer the question on your own.

A relational database is a set of tables from which data can be accessed. This can take place even without the need to reorganize the database tables. The programming interface of a relational database is the Structured Query Language (SQL). This approach was invented by E. F. Codd, who came up with it in 1970 while he was a programmer at IBM.

5 0

3 years ago

An inductor (L = 400 mH), a capacitor (C = 4.43 µF), and a resistor (R = 500 Ω) are connected in series. A 44.0-Hz AC generator

MakcuM [25]

Answer:

(A) Maximum voltage will be equal to 333.194 volt

(B) Current will be leading by an angle 54.70

Explanation:

We have given maximum current in the circuit $i_m=385mA=385\times 10^{-3}A=0.385A$