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
alukav5142 [94]
2 years ago
9

1. A 2.5 kg led projector is launched as a projectile off a tall building. At one point, as it

Physics
1 answer:
spin [16.1K]2 years ago
4 0

Answer:

Explanation:

I got everything but i. Don't know why but it's eluding me. So let's do everything but that.

a. PE = mgh so

   PE = (2.5)(98)(14) and

   PE = 340 J

b. KE=\frac{1}{2}mv^2 so

   KE=\frac{1}{2}(2.5)(14)^2 and

   KE = 250 J

c. TE = KE + PE so

   TE = 340 + 250 and

   TE = 590 J

d. PE at 8.7 m:

   PE = (2.5)(9.8)(8.7) and

   PE = 210 J

e. The KE at the same height:

   TE = KE + PE and

   590 = KE + 210 so

   KE = 380 J

f. The velocity at that height:

   380=\frac{1}{2}(2.5)v^2 and

   v=\sqrt{\frac{2(380)}{2.5} } so

   v = 17 m/s

g. The velocity at a height of 11.6 m (these get a bit more involed as we move forward!). First we need to find the PE at that height and then use it in the TE equation to solve for KE, then use the value for KE in the KE equation to solve for velocity:

   590 = KE + PE and

   PE = (2.5)(9.8)(11.6) so

   PE = 280 then

   590 = KE + 280 so

   KE = 310 then

   310=\frac{1}{2}(2.5)v^2 and

   v=\sqrt{\frac{2(310)}{2.5} } so

   v = 16 m/s

h. This one is a one-dimensional problem not using the TE. This one uses parabolic motion equations. We know that the initial velocity of this object was 0 since it started from the launcher. That allows us to find the time at which the object was at a velocity of 26 m/s. Let's do that first:

   v=v_0+at and

   26 = 0 + 9.8t and

   26 = 9.8t so the time at 26 m/s is

   t = 2.7 seconds. Now we use that in the equation for displacement:

   Δx = v_0t+\frac{1}{2}at^2 and filling in the time the object was at 26 m/s:

   Δx = 0t + \frac{1}{2}(-9.8)2.7)^2 so

   Δx = 36 m

i. ??? In order to find the velocity at which the object hits the ground we would need to know the initial height so we could find the time it takes to hit the ground, and then from there, sub all that in to find final velocity. In my estimations, we have 2 unknowns and I can't seem to see my way around that connundrum.

You might be interested in
A book on a 2-meter high shelf has a mass of 0.4 kg. What is its potential energy?
poizon [28]

Answer:

\boxed {\boxed {\sf 7.84 \ Joules}}

Explanation:

The formula for potential energy is:

PE=m*g*h

where <em>m </em>is the mass, <em>g</em> is the gravitational acceleration, and <em>h</em> is the height.

The mass of the book is 0.4 kilograms. The gravitational acceleration on Earth is 9.8 m/s². The height of the book is 2 meters.

m=0.4 \ kg \\g=9.8 \ m/s^2 \\h=2\ m

Substitute the values into the formula.

PE=(0.4 \ kg)(9.8 \ m/s^2)(2 \ m)

Multiply the first two numbers.

  • 0.4 kg*9.8 m/s²= 3.92 kg*m/s²
  • If we convert the units now, the problem will be much easier later on.
  • 1 kg*m/s² is equal to 1 Newton. So, our answer of 3.92 kg*m/s² is equal to 3.92 N

PE=(3.92 \ N )(2 \ m)

Multiply.

  • 3.92 N* 2 m=7.84 N*m
  • 1 Newton meter is equal to 1 Joule (this is why we converted the units).
  • Our answer is equal to<u> 7.84 Joules.</u>

PE=7.84  \ J

6 0
2 years ago
Read 2 more answers
What is the identify atom shown
Alexus [3.1K]
There is no atom shown..
7 0
3 years ago
An empty elevator has a mass of 722 kg. It moves between floors at a maximum speed of 6.00 m/s. The elevator is stopped on the 2
FinnZ [79.3K]

Answer:

Explanation:

The lift is going down with acceleration

Initial speed u = 0

Final speed v = 6 m/s

distance s = 15.25 m

acceleration a = ?

v² = u² + 2 a s

6² = 0 + 2 x a x 15.25

a = 1.18 m /s²

Elevator is going down with acceleration  .

mg - T = ma where T is tension in the cable .

722 x 9.8 - T = 722 x 1.18

7075.6 - T = 851.96

T = 6223.64 N .

7 0
3 years ago
Which sentences describe central ideas of the video? Select all that apply.
sertanlavr [38]

Answer:

the correct answer is see.

Explanation:

it  is wat it isssssssssss

4 0
3 years ago
The tub of a washer goes into its spin-dry cycle, starting from rest and reaching an angular speed of 5.0 rev/s in 8.0 s. At thi
tatiyna

Answer:

50 revolutions

Explanation:

Data provided:

case I: From rest to top spin

The initial angular speed of the washer, ωi = 0 rev /s

Final angular speed of the washer ωf = 5 rev /s

Time taken, t₁ = 8 s

now,  

The angular displacement or the number of revolutions taken (θ₁) is calculated as:

  θ₁ = ωi t₁ + (1/2)α₁t₁²

where,

α is the angular acceleration

The angular acceleration can be calculated as:

  ωf - ωi = α₁t₁

on substituting the values, we get

8α₁ = 5 - 0

or

α₁ = 0.625 rev/s²

substituting the values in the equation for the number of revolutions, we get

θ₁ = 0 + (1/2) (0.625)(8)²

or

θ₁ = 20 revolutions

also,  

For the case II: From top spin to rest

we have

The initial angular speed, ωi = 5 rev /s

and the final angular speed, ωf = 0 rev /s

Total time taken, t₂ = 12 s

Now, angular acceleration for this case

  ωf - ωi = α₂t₂

on substituting the values, we have

  12α₂ = 0 - 5

α₂ = - 0.4166 rev/s²

Therefore, the number of revolutions ( i.e angular displacement  )

θ₂ = ωit₂ + (1/2)α₂t₂²

on substituting the values, we have

θ₂ = 5 × 12 + (1/2)(-0.4166)(12)²

or

θ₂ = 30 rev

Hence,

the total number of revolutions made by the washer during the 20s is  

θ = θ₁ + θ₂

or

θ = 20 rev + 30 rev

or

θ = 50 revolutions

7 0
2 years ago
Other questions:
  • If a stereo has a dial that changes the volume of sounds the stereo makes what is the dial doing
    14·2 answers
  • Humans obtain energy in a number of different ways. About half of the electrical energy in the U.S. is generated by burning coal
    11·1 answer
  • In order for exercise to be effective, it must substantially increase heart rate. True False
    15·2 answers
  • The velocity of the transverse waves produced by an earthquake is 8.9 km/s, and that of the longitudinal waves is 5.1 km/s. A se
    8·1 answer
  • Large numbers of ribosomes are present in cells that specialize in producing which molecules?
    9·1 answer
  • What is a wavelength?
    14·1 answer
  • Image that Grade 7 students are looking at a spherical ornament that has mirror-like surface. The students exclaim how strange t
    6·1 answer
  • Show that 1.0 m/s = 3.6 km/h . Hint: Show the explicit steps involved in converting 1.0 m/s = 3.6 km/h.
    15·1 answer
  • The transfer of energy between two objects by electromagnetic waves is called
    5·1 answer
  • A cylindrical wire has a length of 2.80 m and a radius of 1.03 mm. It carries a current of current of 1.35 A, when a a voltage o
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!