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
wlad13 [49]
3 years ago
8

A boy exerts a force of 9.0 N horizontally to push his sister on a sled. He pushes her through a distance of 15 m. How much work

did he do?
Was this positive work or negative work? If he stops pushing, his sister and the sled will eventually slow to a stop. Is this negative work or positive
work? What force is doing the work?
Please help with the last 2 questions above^^ (negative or positive,, and what force is doing the work)
Physics
1 answer:
MrRa [10]3 years ago
6 0

Answer:

Work done by the boy is 135 J  and is positive work.

Friction is the force acting that stops the sled and her sister.

Work done by friction is negative work.

Explanation:

Given:

Force acting on the sled by the boy is, F=9.0\ N

Displacement of the sled in the direction of force is, S=15\ m

We know that, positive work is said to be done by a force, if the force causes displacement in its own direction. Also, negative work is said to be done by a force, if the force causes displacement in the direction exactly opposite to the direction of the applied force.

Here, the force applied by the boy causes a displacement in the direction of the applied force. So, work is positive and is given as:

Work = Force × Displacement

Work=F\times S\\Work=9\times 15=135\ J

Therefore, the work done by the boy is positive and equal to 135 J.

Now, when the force of push is removed, then the body will experience only the frictional force in the opposite direction which eventually causes the sled to stop.

Here, the direction of force is backward while the displacement is in the forward direction. So, both of them are in opposite direction.

So, work done by frictional force is negative.

You might be interested in
A student performs a lab measuring the velocities of toy cars of different masses
stiv31 [10]
The answer is Car 1 and Car 2.
5 0
3 years ago
Read 2 more answers
What are the principles of electrodynamic​
Sveta_85 [38]

Answer:

the branch of mechanics concerned with the interaction of electric currents with magnetic fields or with other electric currents.

Explanation:

3 0
3 years ago
0.5 kg air hockey puck is initially at rest. What will it’s kinetic energy be after a net force of .8 N acts on it for a distanc
weqwewe [10]

Answer:

1.6 J

Explanation:

Work = change in energy

W = ΔKE

Fd = KE

(0.8 N) (2 m) = KE

KE = 1.6 J

4 0
3 years ago
Help me with my physics, please
Readme [11.4K]
The right answer would be

-20t+ 80
7 0
3 years ago
Two plastic balls suspended by strings are placed close to each other. If they have the same charge, how will they interact with
vampirchik [111]
<span>Two plastic balls suspended by strings are placed close to each other. If they have the same charge then they will repel each other.</span>
8 0
3 years ago
Read 2 more answers
Other questions:
  • A Sound wave has a frequency of 192 HZ and travels across a football field (91.4m) in 2 seconds. what is the wavelength of the s
    13·1 answer
  • Is it true that newtons laws of universal gravitation states that every object in the universe attracts every other object
    15·1 answer
  • 302,000,000,000 in scientific notation
    7·2 answers
  • The compound LiBr is an example of
    12·1 answer
  • What is the difference between free fall and weightlessness??
    5·1 answer
  • Explain why a basketball doesn’t bounce the same height each time you drop it.
    7·2 answers
  • A tank containing liquid butane and one containing liquid propane are sitting adjacent to one another. each tank is equipped wit
    9·2 answers
  • The magnetic field 0.02 m from a wire is 0.1 t. what is the magnitude of the magnetic field 0.01 m from the same wire?
    14·2 answers
  • How do you determine the acceleration of an object?
    15·1 answer
  • Please help me with this rotation and linear motion problem
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!