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
Bad White [126]
3 years ago
10

If a block of wood dropped from a tall building has attained a velocity of 78.4 m/s how long has it been falling

Physics
1 answer:
ryzh [129]3 years ago
5 0

Gravity adds 9.8 m/s to the speed of a falling object every second.

An object dropped from 'rest' (v = 0) reaches the speed of 78.4 m/s after  falling for (78.4 / 9.8) = <em>8.0 seconds</em> .

<u>Note:</u>

In order to test this, you'd have to drop the object from a really high cell- tower, building, or helicopter.  After falling for 8 seconds and reaching a speed of 78.4 m/s, it has fallen 313.6 meters (1,029 feet) straight down.

The flat roof of the Aon Center . . . the 3rd highest building in Chicago, where I used to work when it was the Amoco Corporation Building . . . is 1,076 feet above the street.

You might be interested in
Someone who wants to sell you a Superball claims that it will bounce to a height greater than the height from which it is droppe
sergeinik [125]

Answer:

No

Explanation:

Unless there are other external forces, this will never be true. Because according to energy conservation, potential energy will be converted to kinetic energy as the ball falls down (so it loses height and gain speed). And vice versa, kinetic to potential when it bounces back. So the potential energy after must be the same (or smaller if losing heat to external environment), so it can only get the the same height or less, but not more.

7 0
3 years ago
Identify the basic structure of a chemical equation
guajiro [1.7K]
The basic structure would be:

Reactants → Products 
6 0
2 years ago
What is the formula for conservation of momentum
olga55 [171]

Answer:

The general equation for conservation of momentum during a collision between n number of objects is given as: [m i ×v i a ] = [m i ×v i b ] Where m i is the mass of object i , v i a is the velocity of object i before the collision, and v i b is the velocity of object i after the collision.

Explanation:

6 0
2 years ago
A fighter jet accelerates from 10 m/s to 75 m/s in 7.0 s. The acceleration of the jet is
liraira [26]
Acceleration = final velocity - inital / time
a = 75-10 / 7
a = 65 / 7
a = 9.29 m/s^2

4 0
2 years ago
The emf induced in a coil that is rotating in a magnetic field will be at a maximum at which moment?
adelina 88 [10]
TLDR: It will reach a maximum when the angle between the area vector and the magnetic field vector are perpendicular to one another.

This is an example that requires you to investigate the properties that occur in electric generators; for example, hydroelectric dams produce electricity by forcing a coil to rotate in the presence of a magnetic field, generating a current.

To solve this, we need to understand the principles of electromotive forces and Lenz’ Law; changing the magnetic field conditions around anything with this potential causes an induced current in the wire that resists this change. This principle is known as Lenz’ Law, and can be described using equations that are specific to certain situations. For this, we need the two that are useful here:

e = -N•dI/dt; dI = ABcos(theta)

where “e” describes the electromotive force, “N” describes the number of loops in the coil, “dI” describes the change in magnetic flux, “dt” describes the change in time, “A” describes the area vector of the coil (this points perpendicular to the loops, intersecting it in open space), “B” describes the magnetic field vector, and theta describes the angle between the area and mag vectors.

Because the number of loops remains constant and the speed of the coils rotation isn’t up for us to decide, the only thing that can increase or decrease the emf is the change in magnetic flux, represented by ABcos(theta). The magnetic field and the size of the loop are also constant, so all we can control is the angle between the two. To generate the largest emf, we need cos(theta) to be as large as possible. To do this, we can search a graph of cos(theta) for the highest point. This occurs when theta equals 90 degrees, or a right angle. Therefore, the electromotive potential will reach a maximum when the angle between the area vector and the magnetic field vector are perpendicular to one another.

Hope this helps!
6 0
3 years ago
Other questions:
  • A sailboat moves north for a distance of 10.00 km when blown by a wind 30° east of south with a force of 5.00 × 104 N. How much
    12·1 answer
  • Which of the following are equivalent unit?
    13·1 answer
  • Two particles are at the same point at the same time, moving in the same direction. Particle A has an initial velocity of 7.6 m/
    7·1 answer
  • What is a cone of depression
    13·1 answer
  • How many ounces in a liter
    8·1 answer
  • Compare the properties of sodium chloride and sand
    6·1 answer
  • What happens if you stick a charged balloon to a metal object?
    13·1 answer
  • A 6.0x10-2kg hollow racquetball with an initial speed of 18.6 m/s collides with a backboard. It rebounds with a speed of 4.6 m/s
    13·1 answer
  • A 26.5-mW laser beam of diameter 1.88 mm is reflected at normal incidence by a perfectly reflecting mirror. Calculate the radiat
    7·1 answer
  • Which proportion can you use to find the value of a? (posted in this category because of bots)
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!