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
Sauron [17]
3 years ago
6

A girl throws a pebble into a deep well at 4.0 m/s (downward). It hits the water in 2.0 s. How far below the ground is the water

's surface? What is the pebble's average velocity?
Physics
1 answer:
alexandr402 [8]3 years ago
8 0

Answer:

  • 27.6 m
  • 13.8 m/s

Explanation:

(b) The initial velocity is added to that due to acceleration by gravity. The velocity is increased linearly by gravity at the rate of 9.8 m/s². The average velocity of the pebble will be its velocity halfway through the 2-second time period.* That is, it will be ...

  4 m/s + (9.8 m/s²)(2 s)/2 = 13.8 m/s . . . . average velocity

__

(a) The distance covered in 2 seconds at an average velocity of 13.8 m/s is ...

  d = vt

  d = (13.8 m/s)(2 s) = 27.6 m

The water is about 27.6 m below ground.

_____

* We have chosen to make use of the fact that the velocity curve is linear, so the average velocity is half the sum of initial and final velocities:

  vAvg = (vInit + vFinal)/2 = (vInit + (vInit +at))/2 = vInit +at/2

__

If you work this in a straightforward way, you would find distance as the integral of velocity, then find average velocity from the distance and time.

  \displaystyle d=\int_0^t{(v_0+at)}\,dt=v_0t+\dfrac{1}{2}at^2=t\left(v_0+a\dfrac{t}{2}\right)\\\\v_{avg}=\dfrac{d}{t}=v_0+a\dfrac{t}{2}\qquad\text{the formula we started with}

You might be interested in
How long will it take, in minutes, for a transformer to transfer 2.3 X 10^6 J of energy from a 120-V circuit to a 345-V circuit
masya89 [10]

Answer:

e

Explanation:

3 0
3 years ago
When and where was the worst hurricane in the united states
Andre45 [30]
It was in Texas on September 8, 1900.
8 0
3 years ago
Any four difference between velocity and acceleration​
pychu [463]

Answer:

https://physicsabout.com/acceleration-and-velcoity/

7 0
3 years ago
Time management skills include
dexar [7]
D. Budgeting time, avoiding stress, and prioritizing.
7 0
3 years ago
Jon's bathtub is rectangular and its base is 18 ft2. (a) How fast is the water level rising if Jon is filling the tub at a rate
Kitty [74]

Answer:

The water level in the bath tub is rising at a rate of 0.0111 ft/s

Explanation:

Volume of the bath tub = (Area of base) × (height)

Area of base = 18 ft² (constant)

Height = h (variable)

V = 18h

(dV/dt) = 18 (dh/dt)

If (dV/dt) = 0.2 ft³/s

0.2 = 18 (dh/dt)

(dh/dt) = (0.2/18)

(dh/dt) = 0.0111 ft/s

Hope this Helps!!!

6 0
3 years ago
Read 2 more answers
Other questions:
  • How does distance between two objects affect their gravitational force?
    12·2 answers
  • Two sections, A and B, are 0.5 km apart along a 0.05 m diameter rough concrete pipe. A is 115 m higher than B, the water tempera
    14·1 answer
  • What is the momentum of a 546,540 kg train that is travelling at 7.8 m/s​
    6·1 answer
  • If a ball is thrown up at an initial speed of 40. m/s, how many seconds does it take to reach the top of its path?
    5·1 answer
  • How<br> to cheat vhhhhhhhhhhhhhhhhhhhh
    6·2 answers
  • A 20 kg box has 1000 joules of potential energy on a shelf. How high is the shelf?
    14·1 answer
  • Calculate the percentage increase in speed of the cyclist when the power output changes from 200 W to 300 W.
    10·1 answer
  • A fruit bat falls from the roof of a cave. We know that her potential energy was
    9·1 answer
  • (b) Which statement about beta radiation is true?
    15·1 answer
  • Hummingbirds may seem fragile, but their wings are capable of sustaining very large forces and accelerations. (Figure 1) shows d
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!