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
bearhunter [10]
3 years ago
5

A tennis ball is dropped from a roof. If it takes 38.9 seconds to reach the ground, how fast is the ball moving just before it h

its the ground? Answer tot he nearest tenths and no units
Physics
1 answer:
Ilya [14]3 years ago
5 0

Answer:

The velocity of the ball before it hits the ground is 381.2 m/s

Explanation:

Given;

time taken to reach the ground, t = 38.9 s

The height of fall is given by;

h = ¹/₂gt²

h = ¹/₂(9.8)(38.9)²

h = 7414.73 m

The velocity of the ball before it hits the ground is given as;

v² = u² + 2gh

where;

u is the initial velocity of the on the root = 0

v is the final velocity of the ball before it hits the ground

v² = 2gh

v = √2gh

v = √(2 x 9.8 x 7414.73 )

v = 381.2 m/s

Therefore, the velocity of the ball before it hits the ground is 381.2 m/s

You might be interested in
What is kinetic energy and what is net force formula
Over [174]

Answer:

Here's the equation for net force: F = ma. The work done on the plane, which becomes its kinetic energy, equals the following: Net force F equals mass times acceleration. Assume that you're pushing in the same direction that the plane is going; in this case, cos 0 degrees = 1, so.

Explanation:

In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes

Hope this help also looking it up helps ;)

6 0
3 years ago
1. Describe the three Newton's Law of Motion.
DIA [1.3K]

Answer:

1st law--Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. This is normally taken as the definition of inertia. The key point here is that if there is no net forceacting on an object (if all the external forces cancel each other out) then the object will maintain a constant velocity. If that velocity is zero, then the object remains at rest. If an external force is applied, the velocity will change because of the force.

2nd— The second law explains how the velocity of an object changes when it is subjected to an external force. The law defines a force to be equal to change in momentum(mass times velocity) per change in time. Newton also developed the calculus of mathematics, and the "changes" expressed in the second law are most accurately defined in differential forms. (Calculus can also be used to determine the velocity and location variations experienced by an object subjected to an external force.) For an object with a constant mass m, the second law states that the force F is the product of an object's mass and its acceleration a:

F = m * a

For an external applied force, the change in velocity depends on the mass of the object. A force will cause a change in velocity; and likewise, a change in velocity will generate a force. The equation works both ways.

3rd law-- The third law states that for every action (force) in nature there is an equal and opposite reaction. In other words, if object A exerts a force on object B, then object B also exerts an equal force on object A. Notice that the forces are exerted on different objects. The third law can be used to explain the generation of lift by a wing and the production of thrust by a jet engine.

8 0
2 years ago
Children are told to avoid standing too close to a rapidly moving train because they might get sucked under it. Is this possible
storchak [24]

Answer:

no its not like the undertow in the ocean

Explanation:

4 0
3 years ago
As a laudably skeptical physics student, you want to test Coulomb's law. For this purpose, you set up a measurement in which a p
kherson [118]

Explanation:

The Coulomb's law states that the magnitude of each of the electric forces between two point-at-rest charges is directly proportional to the product of the magnitude of both charges and inversely proportional to the square of the distance that separates them:

F=\frac{kq_1q_2}{d^2}

In this case we have an electron (-e) and a proton (e), so:

F=-\frac{ke^2}{d^2}\\F=-\frac{8.99*10^9\frac{N\cdot m^2}{s^2}(1.6*10^{-19}C)^2}{(933*10^{-9}m)^2}\\F=-2.64*10^{-16}N

In this case, the electric force is negative, therefore, the force is repulsive and its magnitude is:

F=2.64*10^{-16}N

3 0
3 years ago
How often is water added to the Earth system?
rosijanka [135]
<span>Water is never added to earth system. Water forever remains in the water cycle on earth, so it goes from the ground, to the air, to the rain, to the sea, and round and round continuously. This cycle means that there does not need to be new water added to the earth, because it recycles any water that already exists of its own accord.</span>
4 0
3 years ago
Other questions:
  • A proposed space elevator would consist of a cable stretching from the earth's surface to a satellite, orbiting far in space, th
    6·1 answer
  • A rotating space station is said to create "artificial gravity" - a loosely-defined term used for an acceleration that would be
    9·1 answer
  • A small plastic bead has been charged to -14 nC .
    13·1 answer
  • Compare the gravitational force on a 33 kg mass at the surface of the Earth (with ra-
    6·1 answer
  • An object starts from rest and accelerates at a rate of 3.0 m/s/s for 6.0 seconds. The velocity at the end of the 6.0 seconds is
    9·1 answer
  • A banked circular highway is designed for traffic moving
    13·1 answer
  • Which statements are true about the flow of blood in the body? Check all that apply.
    8·1 answer
  • g it as been suggested that solar powered space ships could get a boost from a laser either on earth or in orbit around earth. t
    8·1 answer
  • Plants make ___________ using carbon dioxide, water and energy from the sun.
    6·1 answer
  • What happens to the the eardrum, a thin membrane at the end of the ear canal, when it is struck by a sound wave?
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!