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
stepan [7]
2 years ago
8

Need help in showing how to get the final velocity​

Physics
1 answer:
kobusy [5.1K]2 years ago
6 0

I don't think the provided solution is correct because it's not dimensionally consistent. The quantity 8h-1 in particular doesn't make sense since it's mixing a distance with a dimensionless constant.

Here's how I think the proper answer should look:

The net force on the box acting perpendicular to the ramp is

\sum F_\perp = F_{\rm normal} - mg \cos(\theta) = 0

where F_{\rm normal} is the magnitude of the normal force due to contact with the ramp and mg\cos(\theta) is the magnitude of the box's weight acting in this direction. The net force is zero since the box doesn't move up or down relative to the plane of motion.

The net force acting parallel the ramp is

\sum F_\| = mg\sin(\theta) - F_{\rm friction} = ma

where mg\sin(\theta) is the magnitude of the parallel component of the box's weight, F_{\rm friction} is the magnitude of kinetic friction, and a is the acceleration of the box.

From the first equation, we find

F_{\rm normal} = mg \cos(\theta)

and since F_{\rm friction} = \mu F_{\rm normal}, we get from the second equation

mg\sin(\theta) - \mu mg\cos(\theta) = ma

and with \mu = 0.25 and \theta=60^\circ, we get

a = g\sin(60^\circ) - 0.25g \cos(60^\circ) = \left(\dfrac{\sqrt3}2 - \dfrac18\right) g

Let x be the length of the ramp, i.e. the distance that the box covers as it slides down it. Then the box attains a final velocity v such that

v^2 = 2ax

From the diagram, we see that

\sin(\theta) = \dfrac hx \implies x = \dfrac h{\sin(60^\circ)} = \dfrac{2h}{\sqrt3}

and so

v^2 = \dfrac{4ah}{\sqrt3} = \left(2 - \dfrac1{2\sqrt3}\right) hg = \dfrac14 \left(8 - \dfrac2{\sqrt3}\right) hg

\implies v = \dfrac12 \sqrt{\left(8 - \dfrac2{\sqrt3}\right) hg}

You might be interested in
Jfdojbfkkjds vdf;ifdfdi
Oliga [24]

Answer:

hsjishhdhjs jdjyshskksndhu

6 0
3 years ago
If the primary of a transformer were connected to a dc power source,
QveST [7]

Answer:

D. only briefly while being connected or disconnected.

Explanation:

As we know that transformer works on the principle of mutual inductance

here we know that as per the principle of mutual inductance when flux linked with the primary coil charges then it will induce EMF in secondary coil

So here when AC source is connected with primary coil then it will give output across secondary coil because AC source will have change in flux with time.

Now when we connect DC source across primary coil then it will not induce any EMF across secondary coil because DC source is a constant voltage source in which flux will remain constant always

So here in DC source the EMF will only induce at the time of connection or disconnection when flux will change in it while rest of the time it will give ZERO output

so correct answer will be

D. only briefly while being connected or disconnected.

8 0
3 years ago
The direction of centripetal force is away from the axis of rotation.
Arada [10]
I’m pretty sure it’s true x
4 0
3 years ago
Read 2 more answers
A converging lens can produce both real and virtual images depending on the position of the object. Explain when converging lens
inessss [21]

Answer: C

Explanation:

5 0
3 years ago
Read 2 more answers
All of the following involve waves of electromagnetic energy except _______.
r-ruslan [8.4K]

All of the following involve waves of electromagnetic energy except the rumble of thunder during a storm.

 

Electromagnetic waves<span> <span>are used to transmit long/short/FM wavelength radio </span>waves, and TV/telephone/wireless signals or energies. They are also responsible for transmiting energy in the form of microwaves, infrared radiation<span> (IR), visible light (VIS), ultraviolet light (UV), X-rays, and gamma rays.</span></span>

 

The correct answer between all the choices given is the second choice or letter B. I am hoping that this answer has satisfied your query and it will be able to help you in your endeavor, and if you would like, feel free to ask another question.

6 0
3 years ago
Read 2 more answers
Other questions:
  • Jkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
    15·1 answer
  • What are the four kinds of air uplift?
    5·1 answer
  • Computer programs like spreadsheets can be used to help organize and analyze data. True or false
    6·2 answers
  • One kilogram-meter per second squared is also equal to what unit
    10·1 answer
  • 2. Derive an expression for the final velocity of an object dropped from some height (h)
    11·1 answer
  • A paper airplane has an acceleration of 5 m/s^2. If it is thrown from rest (0 m/s), how fast will it be going in 3 seconds?
    12·1 answer
  • A man is pushing a box of mass m along the ground with a force F. The coefficient of kinetic friction between the box and the gr
    15·1 answer
  • A mason stretches a string between two points 70 ft apart on the same level with a tension of 20 lb at each end. If the string w
    11·1 answer
  • Which of the following describes the motion or change caused by a transformation from electrical to sound energy? (2 points) a A
    7·2 answers
  • The range of a projectile is found by multiplying which two factors?
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!