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
quester [9]
3 years ago
9

A box is being moved with a velocity (v) by a force P (parallel to v) along a level horizontal floor. The normal force is (Fn),

the kinetic frictional force is (fk), and the weight of the box is (mg). Decide which forces do positivem zero,or negative work.
Physics
1 answer:
labwork [276]3 years ago
8 0

Answer:

Force (P) : Positive

Normal Force (Fn) : Zero

Weight (mg) : Zero

Kinetic Frictional Force (fk) : Negative

Explanation:

The work done by a force on an object is given by the following formula:

W = F.d

W = F d Cosθ

where,

W = Work Done

f = Force Applied

d = displacement

θ = Angle between force and displacement

<u>FOR FORCE (P)</u>:

Since, force P is parallel to the motion of the box. Therefore, θ = 0°

Hence,

W = P d Cos 0°

W = P d(1)

W = Pd

<u>Therefore, work done by force (P) is Positive.</u>

<u></u>

<u>FOR NORMAL FORCE (Fn) AND WEIGHT (W)</u>:

Since, normal force and weight are perpendicular to the motion of the box. Therefore, θ = 90°

Hence,

W = Fn d Cos 90°= mg d Cos 90°

W = Fn d(0) = mg d (0)

W = 0

<u>Therefore, work done by Normal Force (Fn) and Weight (mg) is Zero.</u>

<u></u>

<u>FOR KINETIC FRICTIONAL FORCE (fk)</u>:

Since, kinetic frictional force acts in the opposite direction of motion of the box. Therefore, θ = 180°

Hence,

W = fk d Cos 180°

W = fk d(-1)

W = -fk d

<u>Therefore, work done by Kinetic Frictional Force (fk) is Negative.</u>

<u></u>

You might be interested in
Match these terms with their definitions.
adoni [48]
The correct matches are as follows:

<span>1. measure of disorder 
</span>entropy<span>

2. the study of energy conversions 
</span>thermodynamics 
<span>
3. conservation of energy when heat is added 
</span>second law of thermodynamics 
<span>
4. disorder increasing 
</span>the kinetic and potential energy of the molecules of a substance 
<span>
5. reaching a state of total disorder 
</span>maximum entropy <span>
 
6. internal energy 
first law of thermodynamics</span>
7 0
3 years ago
Read 2 more answers
As time goes on, the ENTROPY in a closed system should increase. This is because of which Law?
olga_2 [115]

Answer:

The answer is D

The second law of thermodynamics

5 0
3 years ago
Please help asap I need this rn
den301095 [7]
It’s the third one .
6 0
3 years ago
As part of an interview for a summer job with the Coast Guard, you are asked to help determine the search area for two sunken sh
marshall27 [118]

Answer:

The resultant velocity is  v_t=10 knots

Explanation:

Apply the law of conservation of momentum

     M_L *v_L + M_f * V_f = (M_L + M_f) v_t

Where M_L is the mass of the Luxury Liner = 40,000 ton

            v_L is the velocity of Luxury Liner = 20 knots due west

            M_f mass of freighter = 60,000

           v_f is the velocity of freighter = 10 knots due north

Apply the law of conservation of momentum toward the the west direction

         v_f = 0 \ knots

So the equation would be

              M_L *v_L = (M_L + M_f) v_t

Substituting values

            40000*20 = (40000+ 60000)v_t_w

Where v_t_w the final velocity due west

Making v_t_w the subject

          v_t_w = \frac{40,000* 20}{(40000 + 60000)}

                = 8 \ knots

Apply the law of conservation of momentum toward the the north direction          

          v_L = 0 \ knots

So the equation would be

           M_f *v_f = (M_L + M_f) v_t_n

Where v_t_n the final velocity due north

     Making v_t_n the subject

          v_t_n = \frac{60,000* 10}{(40000 + 60000)}

                = 6 \ knots

The resultant velocity is

       v_t = \sqrt{v_t_w^2 + v_t_n^2}

            = \sqrt{8^2 +6^2}

           v_t=10 knots

8 0
2 years ago
A thin, light wire 75.2 cm long having a circular cross section 0.560 mm in diameter has a 25.2 kg weight attached to it, causin
blsea [12.9K]

Answer:

The stress is calculated as 1.003\times 10^{9}\ Pa

Solution:

As per the question:

Length of the wire, l = 75.2 cm = 0.752 m

Diameter of the circular cross-section, d = 0.560 mm = 0.560\times 10^{- 3}\ m

Mass of the weight attached, m = 25.2 kg

Elongation in the wire, \Delta l = 1.10\ mm = 1.10\times 10^{- 3}\ m

Now,

The stress in the wire is given by:

Stress,\ \sigma = \frac{Force,\ F}{Area,\ A}          (1)

Now,

Force is due to the weight of the attached weight:

F = mg = 25.2\times 9.8 = 246.96\ N

Cross  sectional Area, A = \pi (\frac{d}{2})^{2} = \pi (\frac{0.560\times 10^{- 3}}{2})^{2} = 2.46\times 10^{- 7}\ m^{2}

Using these values in eqn (1):

\sigma = \frac{246.96}{2.46\times 10^{- 7}} = 1.003\times 10^{9}\ Pa  

8 0
2 years ago
Other questions:
  • Whats the difference between relative dating and absolute dating
    5·2 answers
  • What happens to a star after it goes supernova? Does the remnant of the star form a dwarf star, neutron star, black hole, or som
    8·2 answers
  • SHOW REFRACTION THROUGH A GLASS SLATE WITH NEAT DIAGRAM
    12·2 answers
  • An outfielder with a mass of 86 Kilograms catches a baseball with a mass of 0.15 kilograms.The velocity of the ball just before
    10·1 answer
  • 9
    12·1 answer
  • 1. If all four switches below are turned on, which light bulb will light up? (W is wood, S is silver, and Yis yarn.)
    8·1 answer
  • In handball, once a player possesses the ball,
    7·1 answer
  • What is the helmet for
    10·1 answer
  • A ball is projected at an angle of 53º. If the initial velocity is 48 meters/second, what is the vertical component of the veloc
    6·1 answer
  • In terms of energy transfer, how is a rise in
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!