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3 years ago

7

A lead bar 12 cm long, 2 cm wide, and 2 cm talk has a density of 11.3g/cm3. If you cut the bar in half, what is the density of o

ne of the halves?

1 answer:

VMariaS [17]3 years ago

5 0

Answer:

The density of one halves 11.3 g / cm cube

Explanation:

Density remain same because cutting the bar in half , mass and volume will decrease to half so density will not change .

density = $\frac{mass}{volume}$

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Which is correct about an ammeter?

s344n2d4d5 [400]

Answer:

b. The internal resistance must be much smaller than the other resistances in the circuit.

Explanation:

Ammeter is used to measure the current flowing through a circuit. It is connected in series configuration with the load. In such a scenario the resistance of the ammeter should be negligible so as to make sure that the voltage drop across the resistance of ammeter is zero and it shows the correct reading of the current in the circuit.

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4 years ago

A 3.8kw elective motor powers an inclined conveyer belt. It is designed to lift heavy boxes from the warehouse floor to loading

zhannawk [14.2K]

Answer:

See the answers below

Explanation:

To solve this problem we must use the definition of power and work in physics.

a)

The function of the conveyor belt is to carry the boxes from an initial point that is at low altitude to an end point that is at high altitude. In this way the conveyor belt prints a speed to the box to be able to raise it to the required vertical distance.

Since we have a velocity at the beginning and then we place the box at a high position, where then the box remains at rest, we can say that it converts kinetic energy to potential energy.

b)

Power is defined as the relationship of work over time. Therefore we have:

$P=W/t$

where:

P = power = 3.8 [kW] = 3800 [W]

W = work [J]

t = time = 14 [s]

$W=P*t\\W=3800*14\\W= 53200[J] = 53.2[kJ]$

c)

Since the given time is equal to the given time at Point b, we can use the same work calculated.

We know that work is defined as the product of force by the distance traveled.

$W =F*d$

So, the force is equal to:

$F=W/d\\F=53200/5.3\\F=10037.73[N]$

Now we know that force is defined as the product of mass by gravitation acceleration.

$F =m*g$

where:

F = force or weight = 10037.73 [N]

g = gravity acceleration = 9.81 [m/s²]

m = mass [kg]

$m=F/g\\m = 10037.73/9.81\\m = 1023.2 [kg]$

d)

This part can be solved by means of the energy conservation theorem, where the potential energy is transformed into kinetic energy or vice versa.

$E_{pot}=m*g*h = E_{kin}=0.5*m*v^{2}$

where:

h = elevation = 4.7 [m]

v = velocity [m/s]

$m*g*h=0.5*m*v^{2}\\g*h=0.5*v^{2} \\v=\sqrt{\frac{g*h}{0.5} } \\v=\sqrt{\frac{9.81*4.7}{0.5} } \\v = 9.6 [m/s]$

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3 years ago

What study did james e hansen focus on

Brut [27]

James E. Hansen studied climate change

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2 years ago

Read 2 more answers

A truck covers 47.0 m in 8.60 s while smoothly slowing down to final speed of 2.30 m/s. (a) Find its original speed.

Kruka [31]

Explanation:

Given that,

Distance, s = 47 m

Time taken, t = 8.6 s

Final speed of the truck, v = 2.3 m/s

Let u is the initial speed of the truck and a is its acceleration such that :

$a=\dfrac{v-u}{t}$ .............(1)

Now, the second equation of motion is :

$s=ut+\dfrac{1}{2}at^2$

Put the value of a in above equation as :

$s=ut+\dfrac{1}{2}\times \dfrac{v-u}{t}\times t^2$

$s=\dfrac{t(u+v)}{2}$

$u=\dfrac{2s}{t}-v$

$u=\dfrac{2\times 47}{8.6}-2.3$

u = 8.63 m/s

So, the original speed of the truck is 8.63 m/s. Hence, this is the required solution.

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4 years ago

In general, if the temperature of a chemical reaction is increased, the reaction rateA. IncreasesB. decreasesC. remains the same

In-s [12.5K]

A. Increases

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3 years ago