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
Aleks04 [339]
3 years ago
9

A stone that is dropped freely from rest traveled half its total height in the last second. With what velocity will it strike th

e ground?​
Physics
2 answers:
Paha777 [63]3 years ago
8 0

Answer:

33.5 m/s

Explanation:

At time t, the displacement is h/2:

Δy = v₀ t + ½ at²

h/2 = 0 + ½ gt²

h = gt²

At time t+1, the displacement is h.

Δy = v₀ t + ½ at²

h = 0 + ½ g (t + 1)²

h = ½ g (t + 1)²

Set equal and solve for t:

gt² = ½ g (t + 1)²

2t² = (t + 1)²

2t² = t² + 2t + 1

t² − 2t = 1

t² − 2t + 1 = 2

(t − 1)² = 2

t − 1 = ±√2

t = 1 ± √2

Since t > 0, t = 1 + √2.  So t+1 = 2 + √2.

At that time, the speed is:

v = at + v₀

v = g (2 + √2) + 0

v = g (2 + √2)

If g = 9.8 m/s², v = 33.5 m/s.

VashaNatasha [74]3 years ago
6 0
Let the total distance from the ground be “h” , so the distance travelled in last one second will be “ h/2”. So as it is free fall , u(initial velocity) = 0.
You might be interested in
A hot brass plate is having its upper surface cooled by impinging jet of air at temperature of 15°c and convection heat transfer
Elodia [21]
200 degrees because I need the points
4 0
3 years ago
Consider a mechanical clutch that consists of two heavy disks that can engage or disengage. At the beginning disk 1 with mass m1
miv72 [106K]

Answer:

w = 4,786 rad / s ,  f = 0.76176 Hz

Explanation:

For this problem let's use the concept of angular momentum

       L = I w

The system is formed by the two discs, during the impact the system remains isolated, we have the forces are internal, this implies that the external torque is zero and the angular momentum is conserved

Initial Before sticking

      L₀ = 0 + I₂ w₂

Final after coupling

      L_{f} = (I₁ + I₂) w

The moments of inertia of a disk with an axis of rotation in its center are

      I = ½ M R²

How the moment is preserved

      L₀ = L_{f}

      I₂ w₂ = (I₁ + I₂) w

      w = w₂ I₂ / (I₁ + I₂)

Let's reduce the units to the SI System

      d₁ = 60 cm = 0.60 m

      d₂ = 40 cm = 0.40 m

      f₂ = 200 min-1 (1 min / 60 s) = 3.33 Hz

Angular velocity and frequency are related.

      w₂ = 2 π f₂

      w₂ = 2π 3.33

      w₂ = 20.94 rad / s

Let's replace

       w = w₂ (½ M₂ R₂²) / (½ M₁ R₁² + ½ M₂ R₂²)

       w = w₂ M₂ R₂² / (M₁ R₁² + M₂ R₂²)

Let's calculate

      w = 20.94 8 0.40² / (12 0.60² + 8 0.40²)

      w = 20.94 1.28 / 5.6

      w = 4,786 rad / s

Angular velocity and frequency are related.

      w = 2π f

      f = w / 2π

      f = 4.786 / 2π

      f = 0.76176 Hz

7 0
3 years ago
About 10-15% of all galaxies are which shape?
myrzilka [38]
The answer is; Irregular.
4 0
3 years ago
A girl runs south 10 meters then turns around and walks back 3 meters
Svetlanka [38]

Answer:

12

Explanation:

2iwieie

wjajsjs

sjdide

ejekeo

6 0
3 years ago
A train is accelerating at a rate of 2m/s2. if it's initial velocity is 20 m/s , what is its velocity after 30 seconds
netineya [11]

(v₂-v₁)/t = a

(v₂-20)/30 = 2

v₂-20 = 60

v₂ = 80 m/s

6 0
3 years ago
Other questions:
  • Samanthawalks along a horizontal path in the direction shown the curved path is a semi circle with a radius of 2 m while the hor
    9·1 answer
  • The mechanical advantage of a wheel and axle is the radius of the wheel divided by the radius of the axle. On wheel and axle A,
    11·2 answers
  • Why is density and the melting point both substances of mass
    6·1 answer
  • Which statement about dwarf planets is true?
    11·2 answers
  • Two buses are driving along parallel freeways that are 5mi apart, one heading east and the other heading west. Assuming that eac
    12·1 answer
  • In order to be considered an ion, an atom must have a
    12·1 answer
  • 1. The nearest distance of distinct vision of
    13·1 answer
  • Objects that are denser than water will sink in water. Question 1 options: True False
    7·2 answers
  • Caillou wait no what
    5·2 answers
  • Q|C The speed of a one-dimensional compressional wave traveling along a thin copper rod is 3.56 km/s . The rod is given a sharp
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!