1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
taurus [48]
4 years ago
7

A 30-kg block of ice at 0° C is sliding on a horizontal surface. The initial speed of the ice is 6.1 m/s and the final speed is

4.5 m/s. Assume that the part of the block that melts has a very small mass and that all the heat generated by kinetic friction goes into the block of ice. Determine the mass of ice that melts into water at 0° C.
Physics
1 answer:
S_A_V [24]4 years ago
7 0

Answer:0.748 gm

Explanation:

Given

mass of block =30 kg

initial velocity=6.1 m/s

Final velocity=4.5 m/s

Change in kinetic Energy=\frac{mv_i^2}{2}-\frac{mv_f^2}{2}

\Delta KE=254.4 J

Change in kinetic energy =heat generated by friction=heat  absorbed by ice

L=3.4\times 10^5 J/kg

254.4=m\times 3.4\times 10^5

m=0.748 gm

You might be interested in
This equation is known as the ideal gas law, and it can be used to predict the behavior of many gases at relatively low pressure
Masja [62]
The correct answer is 
<span>C) either the pressure of the gas, the volume of the gas, or both, will increase.

In fact, the ideal gas law can be written as
</span>pV=nRT
<span>where 
p is the gas pressure
V is its volume
n is the number of moles
R is the gas constant
T is the absolute temperature of the gas

We can see that if the temperature T increases, then the term on the right in the equation increases, therefore the term on the left should increase as well. In order for this to be possible, at least one between p and V should increase, or also both of them. Therefore, the correct answer is C.</span>
6 0
3 years ago
Why does a black hole have a stronger gravitational pull than the star that collapse to form it?​
Studentka2010 [4]

Answer:

We consider Black Holes as an object that possesses extreme gravitational pull, but wait aren’t they have the same mass(or less) as that of their parent star. And we know that gravitational pull ‘F’ is directly proportional to the mass of an object, so if the mass is same(or less) then why do black holes have stronger gravity than the stars they evolved from.

The above consideration that F is directly proportional to the mass is partially correct, one should also mention that F is also inversely proportional to the square of the distance between the considered objects.

F = G*(M*m)/(r^2)

Where:

· F is the force acting on you due to star

· M is the mass of Parent star / Black Hole

· m is the mass of an observer, here it is you

· r is the radial distance between the star and you

We know that black hole formed, has much smaller size than that of its parent star and all that mass is compressed to a much smaller scale. If you consider a Star as having a size of an earth then the black hole formed will have a size of small city.

Let us say that you are standing at an r distance away from a star (r>R1), where R1 is the radius of the star, of course (R1>R2), where R2 is the radius of Black Hole.

The Force by which the star in case 1 attracts you will be equal(or less) to the force by which black hole in case 2. So, there is nothing increase in gravitational pull, it is same(or less) as that of the parent star.

Wait a minute, then why people say that black holes have massive gravitational pull.

The gravitational pull increases as we move closer to the black hole, and when we are at its surface, it is enormous as compare to its star surface, because of the difference in the size.

We know that gravitational pull not only depends upon the mass but also depends upon the radial distance between the concerned objects here, it is you and the black hole.

Here, the size of the black hole is much smaller than that of its parent star, i.e (R1>>>R2), and thus we get F1<<<F2, and that is why we say that the black hole has enormous gravitational pull, such that nothing can escape, not even light.

8 0
3 years ago
From the window of a house that is placed 15 m
kow [346]

Answer:

a) 52.915 m

b) The vertical velocity is approximately 21.092 m/s

The resultant velocity is approximately 26.5 m/s

Explanation:

a) The height of the window in the house from which the water was thrown = 15 m

The speed of the stream of water thrown = 20 m/s

The angle at which the water was thrown = 37° over the horizontal

The acceleration due to gravity, g = 10 m/s²

a) The distance from the base of the house at which the water will fall is given as follows;

y = y₀ + u·t·sin(θ) + 1/2·g·t²

Where;

y = The vertical height reached    

u = The initial velocity

t = Time of flight

From the point the steam of water is thrown, we get;

y₀ = 15 m

Therefore;

y = 15 + 20 × t × sin(37°) - 1/2 × 10 × t²

y = 15 + 20 × t × sin(37°) - 5 × t²

When y = 0, Ground level, we get

0 = 15 + 20 × t × sin(37°) - 5 × t²

5·t² - 20×sin(37°)×t -15 = 0

∴ t = (20 ×sin(37°) ± √((-20 × ·sin(37°))² - 4 × (5) × (-15)))/(2 × 5)

t ≈ 3.3128302, or t ≈ 0.906

Therefore, the time of flight of the water, t ≈ 3.3128302 seconds

The distance from the base of the house at which the water will fall = The horizontal distance travelled by the water, x

x = u·cos(θ)×t

∴ x = 20 × cos(37°) × 3.3128302 ≈ 52.915

The distance from the base of the house at which the water will fall = x ≈ 52.915 m

b) The velocity at which the water will reach the ground, 'v', is given as follows;

The vertical velocity, v_y = u·sin(θ)·t - g·t

At the ground, t ≈ 3.3128302 seconds

∴ v_y = 20 × sin(37) - 10 × 3.3128302 ≈ -21.092

The vertical velocity at which the water will reach the ground, v_y ≈ 21.092 m/s (downwards)

The resultant velocity, v = √(v_y² + vₓ²)

∴ v = √(21.092² + (0 × cos(37°))²) ≈ 26.5

The resultant velocity at which the water will reach the ground, v ≈ 26.5 m/s.

5 0
3 years ago
The instantaneous velocity of an object is the blank of the object with a blank
miss Akunina [59]
Instantaneous velocity is the velocity at a specific instant in time. I bet you are taking Honors Physics. 
3 0
4 years ago
Brandon buys a new Seadoo. He goes 22 km north from the beach. He then goes 11km to the east. Then chases a boat 3 km north. Wha
KIM [24]

Answer:

36kms

Explanation:

22+1=33

33+3=36

6 0
3 years ago
Other questions:
  • Consider the two-body situation at the right. A 300kg crate rests on an inclined plane and is connected by a cable to a 100 kg m
    15·1 answer
  • What is the change in internal energy if 60 J of heat are released from a
    9·1 answer
  • It is advised not to hold the thermometer by the bulb while reading it
    12·1 answer
  • The Palo Verde nuclear power generator of Arizona has three reactors that have a combined generating capacity of 3.937×109 W . H
    14·1 answer
  • Nuclear fission can be described as a chain reaction.<br> a. True<br> b. False
    13·2 answers
  • Eric throws a basketball straight up into the air. As it rises, which form of energy is increasing? A. elastic potential energy
    8·2 answers
  • What is meant by the statement "Motion is relativel"?
    14·1 answer
  • An undiscovered planet, many lightyears from Earth, has one moon in a periodic orbit. This moon takes 2060 × 103 seconds (about
    5·1 answer
  • WHAT ARE THREE TECHNICAL ADVANCEMENTS
    14·1 answer
  • How much power do you have if you do 3200 j of work in 18 seconds?
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!