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
dexar [7]
3 years ago
14

A 10 kg box initially at rest is pulled with a 50 N horizontal force for 4 m across a level surface. The force of friction actin

g on the box is a constant 20 N. How much work is done by the normal force pushing up on the box from the ground?
A. 10 J
B. 0 J
C. 100 J
D. 50 J
Physics
1 answer:
emmasim [6.3K]3 years ago
5 0

Answer: 0 j

Explanation:

It is given that,

Mass of the box, m = 10 kg

Force with which the box is pulled, F = 50 N

It is moved a distance of 4 m

Force of friction acting on the box, f = 20 N

We need to find the initial kinetic energy the box have. It is clear that the box is at rest initially. As there is no motion in the box at that time. The formula for the kinetic energy of the box is given by :

As v = 0

So, the initial kinetic energy of the box is 0. Hence, this is the required solution.  

You might be interested in
A laser pulse takes 2.56 seconds to travel from Earth to the Moon and return. Use this to calculate how far away the Moon is. Ho
Deffense [45]

Answer:

x = 3.84\times 10^{5}\,km

This delay affect conversations in the sense that recipient will be receive the message just 2.56 seconds after the message was sent.

Explanation:

The laser pulse has an ondulatory nature as electromagnetic wave, which can travel in the void. Speed of light is constant and distance between Earth and the Moon is:

x = 0.5\cdot c\cdot \Delta t

x = 0.5\cdot (3\times 10^{5}\,\frac{km}{s})\cdot (2.56\,s)

x = 3.84\times 10^{5}\,km

This delay affect conversations in the sense that recipient will be receive the message just 2.56 seconds after the message was sent.

7 0
3 years ago
A box is pushed 40 m by a mover. The amount of work done was 2,240 j. How much force was exerted on the box
Georgia [21]

The force exerted on the box is 56 N

Explanation:

The work done by a force on an object is given by

W=Fd cos \theta

where

F is the magnitude of the force

d is the displacement of the object

\theta is the angle between the direction of the force and of the displacement

For the box in this problem, we have:

W = 2240 J is the work done

d = 40 m is the displacement of the box

Assuming that the  force is parallel to the displacement, \theta=0

Solving the equation for F, we find the force exerted on the box:

F=\frac{W}{d cos \theta}=\frac{2240}{(40)(cos 0)}=56 N

Learn more about work:

brainly.com/question/6763771

brainly.com/question/6443626

#LearnwithBrainly

3 0
3 years ago
A Man Moved first a Distance of 1000 m in 25 second and 2.5 km in 50 second along a in straight line?​
11Alexandr11 [23.1K]

Answer:

Average speed = 46.67 m/s

Explanation:

Given that the time taken in covering first 1000 m = 25 seconds.

The time taken in covering next 2.5 km = 50 seconds.

Total distance covered = 1000 m + 2500 m = 3500 m

Total time taken = 25+50=75 seconds

Average speed = Total distance covered / total time taken

= 3500/75 = 46.67 m/s

3 0
2 years ago
Waves move fastest in
JulijaS [17]
Liquids<span> are not </span>packed<span> as tightly as </span>solids<span>. And gases are very loosely </span>packed<span>. The spacing of the molecules enables </span>sound<span> to travel much faster through a </span>solid<span> than a gas. </span>Sound<span> travels about four times faster and farther in water than it does in air.</span>
4 0
3 years ago
Read 2 more answers
Ai là người phát hiện trái đất hình cầu đầu tiên ?
Scorpion4ik [409]

Answer:

Can't understand the language

5 0
2 years ago
Other questions:
  • When an earthquake occurs, energy radiates in all directions from its source. the source is also referred to as the ________?
    5·2 answers
  • What do u think would happen if a car had all its electrical components (such as windscreens wipers,headlights,blinkers,
    5·1 answer
  • Because of the anode heel effect, where is the intensity of the x-ray beam the greatest?
    13·1 answer
  • Waves with a higher frequency have a ______ wavelength and _____ energy. *
    7·1 answer
  • Which of these waves moves the fastest? <br> a. sound <br> b. radio <br> c. ocean <br> d. seismic
    5·2 answers
  • A certain spring is found not to obey Hooke’s law; it exerts a restoring force Fx(x)=−αx−βx2 if it is stretched or compressed, w
    5·1 answer
  • A liquid with a density of 900kg/m 3 is stored in a pressurized, closed storage tank. The tank is cylindrical with a 10m diamete
    11·1 answer
  • PLEASE HELP ME this is due in 20 mins!!!!!
    9·1 answer
  • I need the answer please
    7·1 answer
  • An astronaut who is repairing the outside of her spaceship accidentally pushes away a 99.1 cm long steel rod, which flies off at
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!