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
Delicious77 [7]
3 years ago
14

A roller coaster car is elevated to a height of 30 m and released from rest to roll along a track. At a certain time T it is at

a height of 2 m and has lost 25.000 J of energy to friction. The car has a mass of 800 kg. Answer the following questions. (a) How fast is the car going at time T? (b) How fast would the car be going at time T if the track were frictionless?
Physics
1 answer:
Naddika [18.5K]3 years ago
4 0

Explanation:

Initial energy = final energy + work done by friction

PE = PE + KE + W

mgH = mgh + 1/2 mv² + W

(800)(9.8)(30) = (800)(9.8)(2) + 1/2 (800) v² + 25000

v = 22.1 m/s

Without friction:

PE = PE + KE

mgH = mgh + 1/2 mv²

(800)(9.8)(30) = (800)(9.8)(2) + 1/2 (800) v²

v = 23.4 m/s

You might be interested in
How does mass effect acceleration
kompoz [17]

Answer:

the bigger the mass the lesser the acceleration and vice versa

Explanation:

this is because the acceleration is a function of the mass and this can be proven by the formula for force: F = ma

7 0
3 years ago
At some instant and location, the electric field associated with an electromagnetic wave in vacuum has the strength 71.9 V/m. Fi
kirza4 [7]

Answer:

a) Magnetic field strength, B = 2.397 * 10⁻⁷ T

b) Total energy density, U = 4.58 * 10⁻⁸ J/m³

c) Power flow per unit area, S = 13.71 W/m²

Explanation:

a) Electric field strength, E = 71.9 V/m

The relationship between the Electric field strength and the magnetic field strength in vacuum is:

E = Bc where c = 3.0 * 10⁸ m/s

71.9 = B * 3.0 * 10⁸

B = 71.9 / (3.0 * 10⁸)

B = 23.97 * 10⁻⁸

B = 2.397 * 10⁻⁷ T

b) Total Energy Density:

U = \frac{1}{2} \epsilon_0E^2 +  \frac{1}{2} \frac{B^2}{\mu_0} \\U = \frac{1}{2}* 8.85 * 10^{-12}*71.9^2 +  \frac{1}{2} \frac{(2.397*10^{-7})^2}{4\pi*10^{-7}}\\U = 2.29 * 10^{-8} + 2.29 * 10^{-8}\\U = 4.58 * 10^{-8} J/m^3

c)Power flow per unit area

S = \frac{1}{\mu_0} EB\\S = \frac{1}{4\pi * 10^{-7} } * 71.9 * 2.397 * 10^{-7}\\S = 13.71 W/m^2

6 0
3 years ago
A submarine is 58.8 m from a whale. The sub sends out a sonar ping to locate the whale. The speed of sound underwater is 1520 m/
MissTica

Answer:

0.08

Explanation:

this problem assume that both of whale and submarine are in rest position or in constant linier motion in same direction and same speed.

The sound will travel from Submarine to the whale and back again to submarine. so the time will be like this

t = 2d/v

t = 2*58.8/1520

t = 117.6/1520

t = 0.077368 s

t ≈ 0.08 s (less then 1 s)

6 0
4 years ago
Guys I just need this question, cmon help me
slavikrds [6]
There can be an experiment run using two or more cleansers at the same time as the manufacturers' one
3 0
3 years ago
Landon attends an early childhood program that is located at a community center which also runs an adult care program.
Ira Lisetskai [31]
Good for Landon. What’s the question?
3 0
3 years ago
Other questions:
  • Explain how the technology of doing math and adding numbers has changed over time this is science
    6·1 answer
  • Sound will not travel through <br> A. A vacuum<br> B. Solids<br> C. Liquids <br> D. Gases
    5·1 answer
  • Match the correct term with each part of the wave
    7·1 answer
  • what changes can be made to the transfer of energy as heat to a heat engine in order to increase the amount of work done by the
    14·1 answer
  • The distance between Neptune and the Sun is 30.06 AU. What is this distance in millions of kilometers? (One AU is about 150 mill
    10·2 answers
  • A sound wave has a speed of 345 m/s and a wavelength of 500 meters. Is it infrasonic, sonic, or ultrasonic
    15·1 answer
  • A scuba diver stays underwater for 30 minutes. How is this possible when the air tank is so small?​
    9·1 answer
  • The cross country team goes on a 10 mile run after school. They end the run outside of the locker room where they started fund t
    6·1 answer
  • Over time Pangaea broke apart to form other continents.
    9·1 answer
  • Through what potential difference must an electron be accelerated from rest to have a de broglie wavelength of 400 nm ?
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!