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
Grace [21]
3 years ago
7

A student, standing on a scale in an elevator at rest, sees that his weight is 840 n. as the elevator rises, his weight increase

s to 1050 n, then returns to normal. when the elevator slows to a stop at the 10th floor, his weight drops to 588 n, and then returns to normal. determine the acceleration at the beginning and end of the trip.
Physics
1 answer:
Firlakuza [10]3 years ago
6 0
<span>1) at rest his weight is 840 N

=> 840N = mass * g => mass = 840 N / g = 840 N / 9.8 m/s^2 = 85.7 kg

2) as the elevator rises, his weight increases to 1050 N,

The reading of the scale is the norma force of it over the body of the person.

And the equation for the force is: Net force = mass * acceleration = normal force - weight at rest

=> mass * acceleration = 1050 N - 840 N = 210 N

acceleration = 210 N / mass = 210 N / 85.7 kg = 2.45 m/s^2 (upward)

3)  when the elevator slows to a stop at the 10th floor, his weight drops to 588 N

=>  mass * acceleration = 588 N - 840 N = - 252 N

=> acceleration = - 252 N / 85.71 kg = - 2.94 m / s^2 (downward)

Answer:

Acceleration at the beginning of the trip 2.45 m/s^2 upward
Acceleration at the end of the trip 2.94 m/s^2 downward
</span>
You might be interested in
The electric potential 1.34 m from a charge is 580 V. What is the value of the charge? Include the sign, + or -. (The answer is
blagie [28]

Answer: 8.6

Explanation:

5 0
2 years ago
In the year 2081 in a shipping port on the moon, workers for Ore-Space, Inc., hoist a 500.0 kg hunk of anorthosite moon rock by
Naddik [55]

Answer:

2,800 n

Explanation:

hope this helps, have a nice day/night! :D

7 0
2 years ago
Lasers are now used in eye surgery. Given the wavelength of a certain laser is 514 nm and the power of the laser is 1.1 W, how m
Leno4ka [110]

Answer: 1.593*10^{17} photons released if the laser is used 0.056 s during the surgery

                           

Explanation:

First, you have to calculate the energy of each photon according to Einstein's theoty, given by:

                            E =\frac{hc}{\lambda}

Where \lambda is the wavelength, h is the Planck's constant and  h is the speed of light

              h = 6.626*10^{-34} \frac{m^{2} kg }{s}  -> Planck's constant

              c = 3*10^{8} \frac{m}{s}  -> Speed of light

So, replacing in the equation:

                E =\frac{ 6.626*10^{-34} \frac{m^{2} kg }{s}*3*10^{8} \frac{m}{s}}{514*10^-9 m}

Then, the energy of each released photon by the laser is:

                E = 3.867*10^{-19} \frac{J}{photons}

After, you do the inverse of the energy per phothon and as a result, you will have the number of photons in a Joule of energy:

               \frac{1}{3.867*10^{-19}} = 2.586*10^{18} \frac{photons}{J}

The power of the laser is 1.1 W, or 1.1 J/s, that means that you can calculate how many photons the laser realease every second:

              2.586*10^{18}\frac{photons}{J} * 1.1 \frac{J}{s} = 2.844*10^{18} \frac{photons}{s}

And by doing a simple rule of three, if 2.844*10^{18} photons are released every second, then in 0.056 s:

            0.056 s*2.844*10^{18} \frac{photons}{s} = 1.593*10^{17} photons are released during the surgery

5 0
3 years ago
Which item(s) would be sufficient to make a circuit?
masya89 [10]

Explanation :

A circuit is the representation of the path of the flow of current. The circuit can be either closed or open.

When the switch is off the circuit is closed circuit and when the switch is not connected the circuit is open.

The items that are sufficient to make a circuit are as follows :

  • Voltage source like a battery.
  • Resistors or electrical equipment like heater, motor etc.

Other components can be ammeter, voltmeter, ac source, variable resistors etc.

7 0
3 years ago
Read 2 more answers
Jack tries to place magnets on his refrigerator at home, but they won’t stick. What could be the reason?
saul85 [17]
The most probable reason why the magnets won't stick on the refrigerator is that the body of the refrigerator and the magnets have like poles. If both have negative or both have positive poles facing each other, they will repel. In principle, magnets are attracted to opposite poles and like poles repel. 
5 0
3 years ago
Other questions:
  • During which time period was the acceleration of the car the greatest?
    5·2 answers
  • How does mass effect my room?
    13·1 answer
  • How is buoyancy used in the real world?​
    7·2 answers
  • You watch a distant lady driving nails into her front porch at a regular rate of 2 strokes per second. You hear the sound of the
    13·1 answer
  • Which of the following graphs shows the relationship between two variables that obey the inverse square law?​
    12·1 answer
  • How much heat is gained by 1.0 gram of iron when its heated 15 degrees celsius
    8·1 answer
  • Question 9
    15·1 answer
  • Calculate the voltage in a circuit where the current is 10amps and the resistance is 6 ohms.​
    7·1 answer
  • What would this one be?
    8·1 answer
  • A double-slit interference pattern is created by two narrow slits spaced 0.21 mm apart. The distance between the first and the f
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!