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
zimovet [89]
3 years ago
12

If state law mandates that elevators cannot accelerate more than 4.80 m/s2 or travel faster than 19.8 m/s , what is the minimum

time in which an elevator can travel the 373 m from the ground floor to the observatory floor?
Physics
1 answer:
Rudik [331]3 years ago
8 0

Answer:

23.0 s

Explanation:

Given:

v₀ = 0 m/s

v = 19.8 m/s

a = 4.80 m/s²

Find: Δx and t

v² = v₀² + 2aΔx

(19.8 m/s)² = (0 m/s)² + 2 (4.80 m/s²) Δx

Δx = 40.84 m

v = at + v₀

19.8 m/s = (4.80 m/s²) t + 0 m/s

t = 4.125 s

The elevator takes 40.84 m and 4.125 s to accelerate, and therefore also 40.84 m and 4.125 s to decelerate.

That leaves 291.3 m to travel at top speed.  The time it takes is:

291.3 m / (19.8 m/s) = 14.71 s

The total time is 4.125 s + 14.71 s + 4.125 s = 23.0 s.

You might be interested in
Does wax paper, aluminum foil, or plastic wrap cause more friction
Levart [38]
Yes i does. they cause more friction <span />
4 0
3 years ago
Read 2 more answers
A ball thrown horizontally at 12.6 m/s from the roof of a building lands 20.0 m from the base of the building
S_A_V [24]

Answer:

1.59 seconds

12.3 meters

but if you are wise you will read the entire answer.

Explanation:

This is a good question -- if not a bit unusual. You should try and understand the details. It will come in handy.

Time

<u>Given</u>

a = 0 This is the critical point. There is no horizontal acceleration.

d = 20 m

v = 12.6 m/s

<u>Formula</u>

d = vi * t + 1/2at^2

<u>Solution</u>

Since the acceleration is 0, the formula reduces to

d = vi * t

20 = 12.6 * t

t = 20 / 12.6

t = 1.59 seconds.

It takes 1.59 seconds to hit the ground

Height of the building

<u>Givens</u>

t = 1.59 sec

vi = 0     Another critical point. The beginning speed vertically is 0

a = 9.8 m/s^2   The acceleration is vertical.

<u>Formula</u>

d = vi*t + 1/2 a t^2

<u>Solution</u>

d = 1/2 a*t^2

d = 1/2 * 9.8 * 1.59^2

d = 12.3 meters.

The two vi's are not to be confused. The horizontal vi is a number other other 0 (in this case 12.6 m/s horizontally)

The other vi is a vertical speed. It is 0.

7 0
3 years ago
An air hockey game has a puck of mass 30 grams and a diameter of 100 mm. The air film under the puck is 0.1 mm thick. Calculate
OverLord2011 [107]

Answer:

time required after impact for a puck is 2.18 seconds

Explanation:

given data

mass = 30 g = 0.03 kg

diameter = 100 mm = 0.1 m

thick = 0.1 mm = 1 ×10^{-4} m

dynamic viscosity = 1.75 ×10^{-5} Ns/m²

air temperature = 15°C

to find out

time required after impact for a puck to lose 10%

solution

we know velocity varies here 0 to v

we consider here initial velocity = v

so final velocity = 0.9v

so change in velocity is du = v

and clearance dy = h

and shear stress acting on surface is here express as

= µ \frac{du}{dy}

so

= µ  \frac{v}{h}   ............1

put here value

= 1.75×10^{-5} × \frac{v}{10^{-4}}

= 0.175 v

and

area between air and puck is given by

Area = \frac{\pi }{4} d^{2}

area  =  \frac{\pi }{4} 0.1^{2}

area = 7.85 × \frac{v}{10^{-3}} m²

so

force on puck is express as

Force = × area

force = 0.175 v × 7.85 × 10^{-3}

force = 1.374 × 10^{-3} v    

and now apply newton second law

force = mass × acceleration

- force = mass \frac{dv}{dt}

- 1.374 × 10^{-3} v = 0.03 \frac{0.9v - v }{t}

t =  \frac{0.1 v * 0.03}{1.37*10^{-3} v}

time = 2.18

so time required after impact for a puck is 2.18 seconds

3 0
3 years ago
Which of the following is true about organizing items and information during scientific investigations?
LekaFEV [45]
There are usually multiple methods for organizing items and information in a scientific investigation.
5 0
3 years ago
Read 2 more answers
When an object is moving away from you while making a sound, the pitch of the sound is perceived to be ___________. lower unchan
Len [333]

the answer is higher

8 0
3 years ago
Read 2 more answers
Other questions:
  • Select the correct answer.
    10·2 answers
  • how did the environment in north america affect the development of american indian culture in period just before europeans arriv
    12·2 answers
  • A charge Q is distributed uniformly on a non-conducting ring of radius R and mass M. The ring is dropped from rest from a height
    15·1 answer
  • Generally, children begin to form a self-concept around ______ months of age.​<br> ​
    10·1 answer
  • What will happen when the sun blows up?
    5·2 answers
  • Hii please help i’ll give brainliest if you give a correct answer please please hurry
    7·1 answer
  • In a closed ring a and in an open ring magnet are falling along the x axis of thrme ring .the current generated in a and b have
    7·1 answer
  • When melting of a metamorphic rock occurs, it changes into what?
    9·1 answer
  • If I walk 30 m north and turn around and walk 10 m to the south, what is the magnitude
    15·2 answers
  • There are two factors that limit how much he can bake in a week: He only wants to work for 40 hours a week and he only has one o
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!