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DochEvi [55]
2 years ago
10

A 248-g piece of copper is dropped into 390 mL of water at 22.6 °C. The final temperature of the water was measured as 39.9 °C.

Calculate the initial temperature of the piece of copper. Assume that all heat transfer occurs between the copper and the water. Remember, the density of water is 1.0 g/m
Physics
1 answer:
Sedaia [141]2 years ago
7 0

Answer:

335°C

Explanation:

Heat gained or lost is:

q = m C ΔT

where m is the mass, C is the specific heat capacity, and ΔT is the change in temperature.

Heat gained by the water = heat lost by the copper

mw Cw ΔTw = mc Cc ΔTc

The water and copper reach the same final temperature, so:

mw Cw (T - Tw) = mc Cc (Tc - T)

Given:

mw = 390 g

Cw = 4.186 J/g/°C

Tw = 22.6°C

mc = 248 g

Cc = 0.386 J/g/°C

T = 39.9°C

Find: Tc

(390) (4.186) (39.9 - 22.6) = (248) (0.386) (Tc - 39.9)

Tc = 335

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Law Incorporation [45]

Answer:

5.32\cdot 10^4 g

Explanation:

First of all, we need to find the volume of the room, which is given by

V=2.50 m \cdot 5.50 m \cdot 3.00 m =41.3 m^3

Now we  can find the mass of the air by using

m=dV

where

d=1.29 g/dm^3 is the density of the air

V=41.3 m^3 = 41,300 dm^3 is the volume of the room

Substituting,

m=(1.29)(41300)=5.32\cdot 10^4 g

6 0
2 years ago
Using the right-hand rule from your lessons, determine the directions of the electrical current and magnetic field of the electr
aliya0001 [1]

Answer:

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Explanation:

This is an accurate representation of something you are working on!

As you can see the wire and the core are represented on the left and is showing how it can be represented on your right hand and how they are similar!

5 0
2 years ago
On her way home from work, Brenda drove 20 miles at 60 miles per hour. Due to poor weather conditions, she then reduced her spee
rjkz [21]

Answer:

D

Explanation:

Speed = distance / time

her time for the first journey = 20 miles / 60 miles/hr = 1/3 hr

her time for second part of the journey = her remaining distance / her speed = (80 - 20) miles / 30 miles/hr = 60 miles / 30 miles/hr = 2 hrs

total time spend by her = 2 hr+ 1/3 hr = 2 1/3 hrs

her traveling the distance at 40 miles per hour = 80 miles / 40 miles /hr = 2 hrs

the time less she would drive if she drive the entire distance at 40 miles/hr =   2 1/3 hrs - 2 hrs = 1/3 hr

3 0
2 years ago
A nucleus whose mass is 3.499612×10^(−25) kg undergoes spontaneous alpha decay. The original nucleus disappears and there appear
Elanso [62]

Answer:

The sum of the kinetic energies of the alpha particle and the new nucleus = (6.5898 × 10⁻¹³) J

Explanation:

Old nucleus ---> New nucleus + alpha particle.

We will use the conservation of energy theorem for extremely small particles,

Total energy before split = total energy after split

That is,

Total energy of the original nucleus = (total energy of the new nucleus) + (total energy of the alpha particle)

Total energy of these subatomic particles is given as equal to (rest energy) + (kinetic energy)

Rest energy = mc² (Einstein)

Let Kinetic energy be k

Kinetic energy of original nucleus = k₀ = 0 J

Kinetic energy of new nucleus = kₙ

Kinetic energy of alpha particle = kₐ

Mass of original nucleus = m₀ = (3.499612 × 10⁻²⁵) kg

Mass of new nucleus = mₙ = (3.433132 × 10⁻²⁵) kg

Mass of alpha particle = mₐ = (6.640678 × 10⁻²⁷) kg

Speed of light = c = (3.0 × 10⁸) m/s

Total energy of the original nucleus = m₀c² (kinetic energy = 0, since it was originally at rest)

Total energy of new nucleus = (mₙc²) + kₙ

Total energy of the alpha particle = (mₐc²) + kₐ

(m₀c²) = (mₙc²) + kₙ + (mₐc²) + kₐ

kₙ + kₐ = (m₀c²) - [(mₙc²) + (mₐc²)

(kₙ + kₐ) = c² (m₀ - mₙ - mₐ)

(kₙ + kₐ) = (3.0 × 10⁸)² [(3.499612 × 10⁻²⁵) - (3.433132 × 10⁻²⁵) - (6.640678 × 10⁻²⁷)]

(kₙ + kₐ) = (9.0 × 10¹⁶)(0.00007322 × 10⁻²⁵) = (6.5898 × 10⁻¹³) J

5 0
2 years ago
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s344n2d4d5 [400]

Answer:

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Explanation:

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The mechanical energy is conserved  

 

      Em = -G m1  M_{earth} / R

      Em = - G m1  M_{earth} / R

     R = int        ⇒  Em = 0

6 0
1 year ago
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