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
Paladinen [302]
3 years ago
14

. A child drops a ball from a window. The ball strikes the ground in 3.0 seconds. What is the. A child drops a ball from a windo

w. The ball strikes the ground in 3.0 seconds. What is the
velocity of the ball the instant before it hits the ground?
Physics
1 answer:
Vsevolod [243]3 years ago
3 0

Answer:

30m/s

Explanation:

  • Use formula for height calculation: Time = √2h/√g
  • From here calculate height which comes out to be: 45m(if g is taken 10)
  • Then use formula for velocity calculation: v = √2gh

  • The velocity comes out to be 30m/s

You might be interested in
Can someone explain the law of conservation of energy?
Bad White [126]
The law of conservation of energy is:

-- Energy can't be created or destroyed.

-- Energy can't just appear out of nowhere.  If you suddenly have
more energy, then the 'extra' energy had to come from somewhere.

-- Energy can't just disappear.  If you suddenly have less energy,
then the 'missing' energy had to go somewhere.
________________________________________

There are also conservation laws for mass and electric charge.
They say exactly the same thing.  Just write 'mass' or 'charge'
in the sentences up above, in place of the word 'energy'.
________________________________________

And now I can tell you that the conservation laws for energy and mass
are actually one single law ... the conservation of mass/energy.  That's
because we discovered about 100 years ago that mass can convert
into energy, and energy can convert into mass, and it's the total of BOTH
of them that gets conserved (can't be created or destroyed).

How much mass makes how much energy ?

The answer is        E = m c²  .

5 0
3 years ago
Kathy 82 kg performer standing on a diving board at the carnival dive straight down into a small pool of water. Just before stri
mixas84 [53]

Solution :

Given weight of Kathy = 82 kg

Her speed before striking the water, $V_o $ = 5.50 m/s

Her speed after entering the water, $V_f$= 1.1 m/s

Time = 1.65 s

Using equation of impulse,

$dP = F \times  dT$

Here, F =  the force ,

       dT =  time interval over which the force is applied for

            = 1.65 s

       dP  = change in momentum

dP = m x dV

    $= m \times [V_f - V_o] $

    = 82 x (1.1 - 5.5)

    = -360 kg

∴ the net force acting will be

$F=\frac{dP}{dT}$

$F=\frac{-360}{1.65}$

  = 218 N

8 0
3 years ago
A motor exerts a force of 12,00N to lift an elevator 8.0m in 7.0secs what is the power produced by the motor?
SashulF [63]

Answer:

1371.4watt

Explanation:

from power=energy/time

BUT energy=force times distance

6 0
3 years ago
What determines velocity rather than speed??
Stella [2.4K]
Velocity - <span><span>the speed of something in a given direction
Speed - </span></span><span>rapidity in moving, going, traveling, proceeding, or performing; swiftness; <span>celerity
Velocity is the speed in a certain direction, whereas speed is just the rate of fastness.
Does that make sense?
</span></span>
3 0
3 years ago
which of the glass lenses above, when placed in air, will cause rays of light (parallel to the central axis) to converge?
777dan777 [17]

Convex lenses when placed in the air, will cause rays of light (parallel to the central axis) to converge.

Converging lenses, commonly referred to as convex lenses, have thicker centers and narrower upper and lower margins. The edges are outwardly curled. This lens has the ability to concentrate a beam of parallel light rays coming from the outside onto a spot on the opposite side of the lens.

The image created is referred to be a genuine image when it is inverted relative to the object. On a screen, this kind of image can be recorded. When the object is positioned at a point farther than one focal length from the lens, a converging lens creates a true image.

A virtual image is one that cannot be produced on a screen and is formed when the image is upright in relation to the object. When an item is positioned within one focal length of a converging lens, a virtual image is created. It creates an enlarged image of the object on the same side of the lens as the image. It serves as a magnifier.

Learn more about the convex lens here:

brainly.com/question/12847657

#SPJ4

3 0
1 year ago
Other questions:
  • A billiard ball travels 23 cm in the positive direction , hits the cushion and rebounds in the negative direction , and Finally
    8·1 answer
  • A block with mass 0.50 kg is forced against a horizontal spring of negligible mass, compressing the spring a distance of 0.20 m
    10·2 answers
  • A study showed the average basal metabolic rate of a human to be about 1500 kcal/day (6279 kJ/day). If it were possible to const
    6·1 answer
  • Air that enters the pleural space during inspiration but is unable to exit during expiration creates a condition called a. open
    6·1 answer
  • How many newtons of force are required to move a 54.87 kg object with an acceleration of 9.8 m/s/s?
    9·1 answer
  • If a runner has a power output of 150 W over 10.0 s, then how much work does she do?
    12·1 answer
  • Kim holds a pinwheel in the air and says it can be used to model a source of energy. Identify the type of energy Kim's pinwheel
    14·1 answer
  • Define Simple harmonic motion (SHM). A body moving with SHM has an amplitude of 10 cm and a frequency of 100 Hz. Find (a) the pe
    10·1 answer
  • A student forgets to turn off a 6.00x 10² W block heater of a car when the weather turns warm. If 14 h goes by before he shuts i
    15·1 answer
  • in a paragraph explain how electncity is generated at a power plant. please don't answer if you don't know ​
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!