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
ASHA 777 [7]
3 years ago
15

A 2.0-kg mass is projected from the edge of the top of a 20-m tall building with a velocity of 24 m/s at some unknown angle abov

e the horizontal. Disregard air resistance and assume the ground is level. What is the kinetic energy of the mass just before it strikes the ground? Answer: 0.97 kJ.
Physics
1 answer:
Digiron [165]3 years ago
3 0

Ox:vₓ=v₀

x=v₀t

Oy:y=h-gt²/2

|vy|=gt

tgα=|vy|/vₓ=gt/v₀=>t=v₀tgα/g

y=0=>h=gt²/2=v₀²tg²α/2g=>tgα=√(2gh/v₀²)=√(2*10*20/24²)=√(400/576)=0.83=>α=tg⁻¹0.83=39°

cosα=vₓ/v=v₀/v=>v=v₀/cosα=24/cos39°=24/0,77=31.16 m/s

Ec=mv²/2=2*31.16²/2=971.47 J=>Ec≈0.97 kJ

You might be interested in
8. A car travels at a constant velocity of 70 mph for one hour. By the end of the second hour, the car’s velocity was 60 mph. At
Mrac [35]

<u>Answer:</u>

  Positive acceleration is in third hour and negative acceleration is in second hour.

<u>Explanation:</u>

  Velocity of car in first hour =  70 mph

  Velocity of car in second hour = 60 mph

  Velocity of car in third hour = 80 mph

   Acceleration = Change in velocity / Time

   Acceleration in second hour = (60 - 70)/1 = -10 mph²

   Acceleration in third hour = (80 - 60)/1 = 20 mph²

   So positive acceleration is in third hour and negative acceleration is in second hour.

8 0
3 years ago
Of the following the only process not involed in the making of clastic rocks is:
Elden [556K]
The answer is B. build up of plant materials. This is because those rocks that are composed of materials, which are organic matters from decaying plants, formed by biological activity are called biogenic or organic or non-clastic rocks. On the other hand, clastic rocks are made up of gravel, sand, silt, and clay.
6 0
3 years ago
Read 2 more answers
Write a hypothesis why the moon has very little liquid water.
Llana [10]
Because the Moon has a very small surface area compared to other spacial geo-bodies, it has cooled down much faster than Earth. Any water on the moon would freeze.
6 0
3 years ago
Please Help!!!!
IgorLugansk [536]
C. Chemical Energy is transformed to light energy and heat energy. The heat energy is keeping you warm and light energy is giving you the light you need to be able to read the book.
8 0
3 years ago
Read 2 more answers
A nonzero net force acts on a particle and does work. Which one of the following statements is true?
arlik [135]

Answer:

option (D) is correct.

Explanation:

According to the work energy theorem, the work done by all forces is equal to the change in kinetic energy of the body.

the kinetic energy of a body is directly proportional to the square of the speed of the body.

As the kinetic energy change, the speed of the body also change.

Option (D) is correct.

5 0
3 years ago
Other questions:
  • The wavelength of some green light is 530.0 nm. what is the frequency of this green light?
    9·1 answer
  • Do y’all know the answers to them all the choices are at the drop down box.!!!
    6·2 answers
  • To understand the standard formula for a sinusoidal traveling wave. One formula for a wave with a y displacement (e.g., of a str
    5·1 answer
  • A student wants to determine whether an unknown solid is an ionic compound. He puts some in water and finds that it does not dis
    14·1 answer
  • How much time would it take to go up to the moon and back
    10·2 answers
  • How to find capacitance of a conductor?
    7·1 answer
  • Block A can slide relative to block B which, in turn, can slide on a perfectly smooth horizontal plane. If the initial velocity
    12·1 answer
  • Describe how the potential energy changes
    8·2 answers
  • Pilots often take advantage of the ____,which are highly-speed winds between 7km and 16 km above earths surface.
    9·1 answer
  • Help me and I'll make u Brainliest and follow u
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!