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
lesantik [10]
3 years ago
5

A system of two objects has ΔKtot = 6 J and ΔUint = -5 J. Part A How much work is done by interaction forces? Express your answe

r as an integer. Part B
How much work is done by external forces?
Express your answer as an integer.
Physics
1 answer:
Elina [12.6K]3 years ago
5 0

A) +5 J

B) +1 J

Explanation:

A)

The internal forces (interaction forces) acting on a system do not change the mechanical energy (sum of potential and kinetic energy) of the system.

However, these forces are responsible for converting the energy from one form into another; the work done by these forces is equal to the amount of energy converted from one form into the other.

In this problem, we have:

\Delta U=-5 J is the loss in potential energy of the system

\Delta K=+6 J is the gain in kinetic energy of the system

By looking at these numbers, this means that the internal forces have converted 5 J of energy from potential energy into kinetic energy (while the additional +1 J missing is due to external forces, as explained in part B).

Therefore, the work done by internal forces is

W = +5 J

B)

First of all, we calculate the change in mechanical energy of the system.

The mechanical energy of a system is the sum of its kinetic energy (K) and its potential energy (U):

E=K+U

So, the change in mechanical energy is equal to the sum of the changes of kinetic energy and the changes of potential energy:

\Delta E= \Delta K + \Delta U

In this problem:

\Delta K=+6 J

\Delta U=-5 J

So, the change in mechanical energy is:

\Delta E=+6+(-5)=+1 J

According to the work-energy theorem, the work done by external forces on a system is equal to the change in mechanical energy of the system: therefore in this case, the work done by external forces is

W=\Delta E=+1 J

You might be interested in
a concrete slab 20 m long and weighing 400,000 N is supported by one pillar. A 19,600 N car is parked 8 meters from one end, whe
Elden [556K]

let the distance of pillar is "r" from one end of the slab

So here net torque must be balance with respect to pillar to be in balanced state

So here we will have

Mg(r - L/2) = mg(L/2 - 8)

here we know that

mg = 19600 N

Mg = 400,000 N

L = 20 m

from above equation we have

400,000(r - 10) = 19,600 (10 - 8)

r - 10 = 0.098

r = 10.098 m

so pillar is at distance 10.098 m from one end of the slab

3 0
3 years ago
Trong thí nghiệm Y-âng về giao thoa ánh sáng : khoảng cách giữa hai khe là 0,5 mm ; khoảng cách từ mặt phẳng chứa hai khe đến mà
Natalija [7]

không có câu hỏi, trả lời như nào nhỉ?

8 0
3 years ago
Read 2 more answers
Isaac Newton published his work on gravity in the Philosophiæ Naturalis Principia Mathematica (Latin for Mathematical Principles
Igoryamba
Today we can make observations that would lead us to the same conclusion as newton. If you throw a baseball in the air, it always comes back down. This is because of gravity. duh.
6 0
3 years ago
Post WWII Germany was divided into four zones with the Americans occupying one zone and all of the following countries occupying
maxonik [38]

Answer:

b. Italy

Explanation:

Italy had sided with germany and lost in world war 2

After the Potsdam conference, Germany was divided into four occupied zones: Great Britain in the northwest, France in the southwest, the United States in the south and the Soviet Union in the east.

europeuncedu

3 0
2 years ago
A 20-kg child is tossed up into the air by her parent. The child is 2 meters off the ground traveling 5 m/s.
nignag [31]
The kinetic energy (KE) is 250 J and the gravitational potential energy (GPE) is 392 J
4 0
3 years ago
Other questions:
  • How do you convert pounds into newtons?
    9·1 answer
  • How does the length and width of a flute affect its sound?
    11·1 answer
  • An asteroid orbits the Sun at an average distance of a= 4 AU. How long does it take to orbit the Sun?Use Kepler’s Third Law(p2=
    5·1 answer
  • Two charged particles are a distance of 1.62 m from each other. One of the particles has a charge of 7.10 nc, and the other has
    9·1 answer
  • A car is driven 110 km west and then 40 km southwest, how far is the car from the point of origin?
    11·1 answer
  • A sound is recorded at 19 decibels. What is the intensity of the sound?
    10·1 answer
  • If a truck weighs 18,000 N and it’s tires are inflated to a pressure of 190 kPa how large is the area of the trucks tires that a
    6·1 answer
  • The drawings show three examples of the force with which someone pushes against a vertical wall. In each case the magnitude of t
    5·2 answers
  • According to Newton’s first law of motion, a moving object that is not acted on by an unbalanced force will..
    8·2 answers
  • Which of the following is an example of a healthy behavior?
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!