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
Digiron [165]
3 years ago
7

My questions are in the picture: Please help.

Physics
1 answer:
frutty [35]3 years ago
8 0

Answer:

a.)

I.) Open system

II.) Closed system

b.)

The total momentum of the object and earth system stay the same as the object fall toward the earth

The kinetic energy of the object increases as the object falls toward the earth.

Explanation:

a.)

I.) The system containing only the object is an open system because of the influence of external forces and presence of matters. External forces in this scenario means gravitational force acting on the object. And air is the matter that has influence on the object.

II.) The system containing only the object and earth is a closed system. Because in a closed system, there are no external dissipative forces acting on it. Universe is a closed system. And the mechanical energy of a close system is conserved. The mechanical energy will remain constant. In other words, it will not change (become more or less). This is called the Law of Conservation of Mechanical Energy.

b.) The total momentum of the object and earth system stay the same as the object fall toward the earth. Because momentum will always be conserved.

The kinetic energy of the object increases as the object falls toward the earth. When the object was initially at rest, kinetic energy equals zero

You might be interested in
What causes the granular structure on the sun's photosphere?
Charra [1.4K]
Something to do with how the suns magnetic field interacts with the surface plasmas I think.
4 0
3 years ago
Dwayne ‘The Rock’ Johnson needs to escape from the fourth floor of a burning building (in a movie). He ties a rope around his wa
ZanzabumX [31]

Answer:

Final Speed of Dwayne 'The Rock' Johnson = 15.812 m/s

Explanation:

Let's start out with finding the force acting downwards because of the mass of 'The Rock':

Dwayne 'The Rock' Johnson: 118kg x 9.81m/s = 1157.58 N

Now the problem also states that the kinetic friction of the desk in this problem is 370 N

Since the pulley is smooth, the weight of Dwayne Johnson being transferred fully, and pulls the desk with a force of 1157.58 N. The frictional force of the desk is resisting this motion by a force of 370 N. Subtracting both forces we get the resultant force on the desk to be: 1157.58 - 370 = 787.58 N

Now lets use F = ma to calculate for the acceleration of the desk:

787.58 = 63 x acceleration

acceleration = 12.501 m/s

Finally, we can use the motion equation:

v^2 - u^2 = 2*a*s

here u = 0 m/s (since initial speed of the desk is 0)

a = 12.501 m/s

and s = 10 m

Solving this we get:

v^2 - 0 = 2 * 12.501 * 10

v = 15.812 m/s

Since the desk and Mr. Dwayne Johnson are connected by a taught rope, they are travelling at the same speed. Thus, Dwayne also travels at            15.812 m/s when the desk reaches the window.

5 0
3 years ago
You are standing on a large sheet of frictionless ice and holding a large rock. In order to get off the ice, you throw the rock
kondor19780726 [428]

Answer:

0.4778 m/s

Explanation:

To solve this question, we will make use of law of conservation of momentum.

We are given that the rock's velocity is 12 m/s at 35°. Thus, the horizontal component of this velocity is;

V_x = (12 m/s)(cos(35°)) = 9.83 m/s.

Thus, the horizontal component of the rock's momentum is;

(3.5 kg)(9.83 m/s) = 34.405 kg·m/s.

Since the person is not pushed up off the ice or down into it, his momentum will have no vertical component and so his momentum will have the same magnitude as the horizontal component of the rock's momentum.

Thus, to get the person's speed, we know that; momentum = mass x velocity

Mass of person = 72 kg and we have momentum as 34.405 kg·m/s

Thus;

34.405 = 72 x velocity

Velocity = 34.405/72

Velocity = 0.4778 m/s

6 0
3 years ago
Donna drove to the mountains last weekend. There was heavy traffic on the way there, and the trip took 8 hours. When Donna drove
Dennis_Churaev [7]

Answer:

d=360 miles

Donna lives 360 miles from the mountains.

Explanation:

Conceptual analysis

We apply the formula to calculate uniform moving distance[

d=v*t   Formula (1)

d: distance in miles

t: time in hours

v: speed in miles/hour

Development of problem

The distance Donna traveled to the mountains is equal to the distance back home, equal to d,then,we pose the kinematic equations for d, applying formula 1:

travel data to the mountains: t₁= 8 hours ,  v=v₁

d= v₁*t₁=8*v₁ Equation (1)

data back home : t₂=4hours ,  v=v₂=v₁+45

d=v₂*t₂=(v₁+45)*4=4v₁+180 Equation (2)

Equation (1)=Equation (2)

8*v₁=4v₁+180

8*v₁-4v₁=180

4v₁=180

v₁=180÷4=45 miles/hour

we replace v₁=45 miles/hour in equation (1)

d=8hour*45miles/hour

d=360 miles

8 0
2 years ago
Fitness results come from hard work, not an instant fix<br> Question 1 options:<br> True<br> False
zhannawk [14.2K]
<span>This is a true statement. Fitness is typically a long-term solution, not a short-term repair. When looking for fitness results, it will usually take weeks to months to see any tangible results, even though there could be some short-term benefits such as increased energy. This is why fitness is sometimes seen as a lifetime endeavor and not one that occurs overnight.</span>
5 0
3 years ago
Other questions:
  • While Calvin is doing a physics experiment outside with a radar gun, he notices that after three seconds a car reaches a speed o
    9·1 answer
  • If two firecrackers produce a sound level of 81 dBdB when fired simultaneously at a certain place, what will be the sound level
    7·1 answer
  • A 0.25-kg coffee mug is made from a material that has a specific heat capacity of 950 J/(kg · C°) and contains 0.30 kg of water.
    6·1 answer
  • If you were told an atom was an ion, you would know the atom must have a...
    13·1 answer
  • Mr. Nakamora wants to test the accuracy of an old balance in his classroom compared to a brand-new balance that he knows is accu
    14·2 answers
  • How much work is done (in Joules) by a weightlifter in raising a 60-kg barbell from the floor to a height of 2m? Work done =
    12·2 answers
  • You want to create an electric field vector E = &lt; 0, 5 104, 0&gt; N/C at location &lt; 0, 0, 0&gt;. Where would you place a p
    14·1 answer
  • Point charge μC is located at x =, y = , point charge is located at x = 0m. What are (a)the magnitude and (b)direction of the to
    11·1 answer
  • At an instant in time, the electric and magnetic fields of an electromagnetic wave are given by - -6.25 x 10-3 v/m and B = -2.08
    7·1 answer
  • There are many uses for permanent magnets and temporary magnets like an electromagnet. Electric appliances with electric motors
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!