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
Kruka [31]
3 years ago
12

A motorist is driving at 20m/s when she sees that a traffic light 200m ahead has just turned red. She knows that this light stay

s red for 15s, and she wants to reach the light just as it turns green again. It takes her 1.0s to step on the brakes and begin slowing. What is her speed as she reaches the light at the instant it turns green?
Physics
1 answer:
yuradex [85]3 years ago
4 0

Answer:

5.71428571422 m/s

Explanation:

u = Initial velocity = 20 m/s

v = Final velocity

s = Displacement

a = Acceleration

Time taken = 15-1 = 14 s

Distance traveled in 1 second = 20\times 1=20\ m

s=ut+\frac{1}{2}at^2\\\Rightarrow 200-20=20\times 14+\frac{1}{2}\times a\times 14^2\\\Rightarrow a=\frac{2(180-20\times14)}{14^2}\\\Rightarrow a=-1.02040816327\ m/s^2

v=u+at\\\Rightarrow v=20-1.02040816327\times 14\\\Rightarrow v=5.71428571422\ m/s

The speed as she reaches the light at the instant it turns green is 5.71428571422 m/s

You might be interested in
Explain the importance of having a support network when trying to achieve a healthy lifestyle. Who supports you when it comes to
Vadim26 [7]

Answer:

Who are the people for you then I can help you format the essay

Explanation:

7 0
2 years ago
Read 2 more answers
Define the strip attached to the magnet?​
Aleonysh [2.5K]

Answer:

A stripe of magnetic information that is affixed to the back of a plastic credit or debit card.

5 0
3 years ago
How far away is Earth from the Sun?
Snowcat [4.5K]
<span>d. 93 billion miles

</span>Earth, being the third planet from the sun is unique in the universe  because it is currently the only planet known to support life. Earth's distance from the sun is really one of  the key reasons why it is has widespread  life.Earth occupies what scientists sometimes call the Goldilocks zone. Its distance from the sun means its neither too hot nor too cold to support liquid water. Water is thought to be a key ingredient for life.<span> The energy from the sun in just the right intensity and the availability of water on the earth make it possible for life to thrive on earth. Plants use both these resources for photosynthesis and make nutrients that are available to support the life of animals on the earth. </span>
6 0
2 years ago
Read 2 more answers
Express the kinetic energy K in terms of the potential energy U.<br><br><br> K=GMm/2R
max2010maxim [7]

Answer:

K = -½U

Explanation:

From Newton's law of gravitation, the formula for gravitational potential energy is;

U = -GMm/R

Where,

G is gravitational constant

M and m are the two masses exerting the forces

R is the distance between the two objects

Now, in the question, we are given that kinetic energy is;

K = GMm/2R

Re-rranging, we have;

K = ½(GMm/R)

Comparing the equation of kinetic energy to that of potential energy, we can derive that gravitational kinetic energy can be expressed in terms of potential energy as;

K = -½U

7 0
3 years ago
Which property of light remains unchanged when it enters a different medium?
Amiraneli [1.4K]
The FREQUENCY of light remains unchanged once it leaves the source.
3 0
3 years ago
Read 2 more answers
Other questions:
  • Porque alguno satélites de telecomunicaciones puede permanecer en una orbita geoestacionaria
    14·1 answer
  • A bicycle tire is spinning counterclockwise at 2.70 rad/s. During a time period Δt = 1.50 s, the tire is stopped and spun in the
    14·2 answers
  • A 2 kg soccer ball is traveling 28.62m/s when it hits the wall and bounces off of the wall with a velocity of 20 m/s. If the wal
    9·1 answer
  • Find the potential energy of a 50gof mass 10kg standing on a building floor of 10m above the ground level​
    13·1 answer
  • PLEASE HELP ASAP!!! CORRECT ANSWER ONLY PLEASE!!!<br><br> Which wave has the greatest frequency?
    12·1 answer
  • I need help by today guys plz help
    14·1 answer
  • A 400-kg space probe has a weight of 3,560 N on one of the above planets. According to the table
    7·1 answer
  • Ayuda porfa es de actividades fisicas
    10·1 answer
  • Which method is responsible for the transfer of heat in the atmosphere ?
    6·1 answer
  • How are asteroids and comets similar? (1 point)
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!