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3 years ago

Jana lifted a 200-newton weight over her head to a distance of 2 meters above the ground. How much work did she do?

Physics

1 answer:

ira [324]3 years ago

4 0

Work = force * distance

force = 200 N
distance = 2m

Work = 200 * 2 = 400 J of work done.

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What is the net force on a car moving in a straight line with a constant velocity

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Answer:

For example, when a car travels at a constant speed, the driving force from the engine is balanced by resistive forces such as air resistance and friction in the car's moving parts. The resultant force on the car is zero.

Explanation:

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2 years ago

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Answer:

The galaxies outside of our own are moving away from us, and the ones that are farthest away are moving the fastest. This means that no matter what galaxy you happen to be in, all the other galaxies are moving away from you

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2 years ago

Azurite is a mineral that contains 55.1% of copper. How many meter of copper wire with diameter of 0.0113 in can be produced fro

soldier1979 [14.2K]

Answer:

1402.73 m

Explanation:

Mass of Azurite=3.25 lb

Percent of copper in AZurite mineral=55.1%

Diameter of copper wire,d=0.0113 in

Radius of copper wire= $r=\frac{d}{2}=\frac{0.0113}{2}=0.00565 in=\frac{565}{100000}=\frac{565}{100}\times \frac{1}{1000}=5.65\times 10^{-3}in$

$\frac{1}{1000}=10^{-3}$

Density of copper= $\rho=8.96g/cm^3$

1 lb=454 g

3.25 lb= $3.25\times 454=1475.5 g$

Mass of Azurite= $1475.5 g$

Mass of copper= $\frac{55.1}{100}\times 1475.5=813 g$

Density= $\frac{Mass}{volume}$

Using the formula

$8.96=\frac{813}{volume\;of\;copper}$

Volume of copper wire= $\frac{813}{8.96}=90.7cm^3$

Radius of copper wire= $5.65\times 10^{-3}\times 2.54=14.35\times 10^{-3} cm$

1 in=2.54 cm

Volume of copper wire= $\pi r^2 h$

$\pi=3.14$

Using the formula

$90.7=3.14\times (14.35\times 10^{-3})^2\times h$

$h=\frac{90.7}{3.14\times (14.35\times 10^{-3})^2}$

$h=140273 cm$

1 m=100 cm

$h=\frac{140273}{100}=1402.73 m$

Hence, the length of copper wire required=1402.73 m

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3 years ago

To pull a 57 kg crate across a horizontal frictionless floor, a worker applies a force of 230 N, directed 34° above the horizont

lisabon 2012 [21]

Answer:

$a. W_w=235\ J\\b. W_g=-343.54\ J\\c. F_N=463.100\ N\\d. W_t=235\ J$

Explanation:

Given: that,

Angle of inclination of the surface, $\theta=34^{\circ}$

mass of the crate, $m=57\ kg$

Force applied along the surface, $F=230\ N$

distance the crate moves after the application of force, $s=1.1\ m$

a) work done = F× s

work done = 230 × 1.1

work done = 253 J

b) Work done by the gravitational force:

$W_g=m.g\times h$

where:

g = acceleration due to gravity

h = the vertically downward displacement

Now, we find the height:

$h=s\times sin\ \thetah=1.1\times sin\ 34^{\circ}h=0.615\ m$

So, the work done by the gravity:

$W_g=57\times 9.8\times (-0.615) \\= - 343.54 J$

∵direction of force and displacement are opposite.

= - 343.54J

The normal reaction force on the crate by the inclined surface:

$F_N=m.g.cos\ \thetaF_N=57\times 9.8\times cos\ 34F_N=463.100\ N$

Total work done on crate is with respect to the worker:

$W_t=235\ J$

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3 years ago

If a train conductor is describing the speed of the train as well as the direction of the train is going to then the train condu

dolphi86 [110]

Answer:

With all of that information, he's telling us the train's VELOCITY.

Explanation:

Velocity is a vector quantity made of two parts: speed and direction.

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3 years ago