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3 years ago

13

You just found a metallic object in a creek bed. you have found its mass to be 96.5 g, and it displaces 5mL of water. what is th

e substance?
A.) aluminum
B.)iron
C.)gold
D.)none of the above

2 answers:

MaRussiya [10]3 years ago

4 0

Judging by the density (19.3 g/ml) there's a very good chance that it could be gold.

Amanda [17]3 years ago

4 0

Answer:

C) gold

Explanation:

Given:

Mass of the object = 96.5 g

Volume of water displaced= 5 ml

Formula:

$Density = \frac{Mass}{Volume} \\Density of metal =\frac{96.5 g}{5ml} = 19.3 g/ml$

The known densities of Al, Fe and Au are:

Density of Al = 2.7 g/ml

Density of Iron (Fe)= 7.87 g/ml

Density of gold (Au) = 19.3 g/ml

Therefore, the metallic object is gold

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Imagine you could travel to the moon where the acceleration due to gravity is 1.6 m/s^2. What would be the period of

VladimirAG [237]

Answer:

4.9612 s

Explanation:

Applying,

T = 2π√(L/g)............... Equation 1

Where T = period of the pendulum, L = Lenght of the pendulum, g = acceleration due to gravity of the moon, π = pie.

From the question,

Given: L = 1 m, g = 1.6 m/s²

Constant: π = 3.14

Substitute these values into equation 1

T = 2×3.14×√(1/1.6)

T = 6.28√(0.625)

T = 6.28×0.79

T = 4.9612 s

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13. How many electrons does a complete third electron shell hold?

ale4655 [162]

Answer:

A) 8

<u>A complete third electron shell holds </u><u>8</u><u> electrons</u>

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3 years ago

An aluminum calorimeter with a mass of 100 g contains 250 g of water. The calorimeter and water are in thermal equilibrium at 10

Alexeev081 [22]

Answer:

a) $c=1822.3214\ J.kg^{-1}.K^{-1}$

b) This value of specific heat is close to the specific heat of ice at -40° C and the specific heat of peat (a variety of coal).

c) The material is peat, possibly.

d) The material cannot be ice because ice doesn't exists at a temperature of 100°C.

Explanation:

Given:

mass of aluminium, $m_a=0.1\ kg$

mass of water, $m_w=0.25\ kg$

initial temperature of the system, $T_i=10^{\circ}C$

mass of copper block, $m_c=0.1\ kg$

temperature of copper block, $T_c=50^{\circ}C$

mass of the other block, $m=0.07\ kg$

temperature of the other block, $T=100^{\circ}C$

final equilibrium temperature, $T_f=20^{\circ}C$

We have,

specific heat of aluminium, $c_a=910\ J.kg^{-1}.K^{-1}$

specific heat of copper, $c_c=390\ J.kg^{-1}.K^{-1}$

specific heat of water, $c_w=4186\ J.kg^{-1}.K^{-1}$

Using the heat energy conservation equation.

The heat absorbed by the system of the calorie-meter to reach the final temperature.

$Q_{in}=m_a.c_a.(T_f-T_i)+m_w.c_w.(T_f-T_i)$

$Q_{in}=0.1\times 910\times (20-10)+0.25\times 4186\times (20-10)$

$Q_{in}=11375\ J$

The heat released by the blocks when dipped into water:

$Q_{out}=m_c.c_c.(T_c-T_f)+m.c.(T-T_f)$

where

$c=$ specific heat of the unknown material

For the conservation of energy : $Q_{in}=Q_{out}$

so,

$11375=0.1\times 390\times (50-20)+0.07\times c\times (100-20)$

$c=1822.3214\ J.kg^{-1}.K^{-1}$

b)

This value of specific heat is close to the specific heat of ice at -40° C and the specific heat of peat (a variety of coal).

c)

The material is peat, possibly.

d)

The material cannot be ice because ice doesn't exists at a temperature of 100°C.

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3 years ago

A ball is thrown vertically upwards with a velocity of 9.8 m/s. Its velocity after 1 second will be

Reil [10]

$\LARGE{ \underline{\underline{ \purple{ \bf{Required \: answer:}}}}}$

GiveN:

Initial velocity = 9.8 m/s²
Accleration due to gravity = -9.8 m/s²
Time taken = 1 s

To FinD:

Final velocity of the ball?

Step-by-step Explanation:

Using the first Equation of motion,

⇒ v = u + gt

⇒ v = 9.8 + -9.8(1)

⇒ v = 0 m/s

The final velocity is hence <u>0</u><u> </u><u>m</u><u>/</u><u>s</u><u>.</u>

<h3>Note:</h3>

While solving questions of under gravity motions using equations of motion, remember the sign convection to avoid mistakes.
You can consider positive above the ground and negative for towards it.

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24 How long does it take for the Earth to orbit the Sun?

Zarrin [17]

Answer:

365 days

So The Final Answer is a Year

D is the answer

Explanation:

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