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
Mariulka [41]
2 years ago
5

A ranger in a national park is driving at 11.8mi / h when a deer jumps into the road 242 ft ahead of the vehicle. After a reacti

on time of t the ranger applies the brakes to produce and acceleration of -9.18ft/s^2 What is the maximum reaction time allowed if she is to avoid hitting the deer? Answer in units of s.
Physics
1 answer:
pogonyaev2 years ago
7 0

Answer:

The maximum reaction time is approximately 13 seconds

Explanation:

In order to answer this problem let's start by converting the speed of the ranger's vehicle from miles per hour into feet per second, knowing that 1 mile is the same as 5280 ft and i hour is 3600 seconds:

11.8\,  \frac{mi}{h} =11.8 \,\frac{5280\,ft}{3600\,s} \approx 17.3\,\frac{ft}{s}

Now, with this information, we set the equation for the amount of time needed to reduce the speed from 17.3 ft/s to full stop (0 ft/s):

v_f-v_i=-9.18 \,t\\0-17.3=-9.18\,t\\t=\frac{17.3}{9.18} \,s\\t\approx 1.88\,s

Now, the space covered during these 1.88 s when the vehicle reaches full stop while it decelerates is calculated via:

x_f-x_i=v_i\,t + \frac{1}{2} a\,t^2\\x_f-x_i=17.3\,t-\frac{9.18}{2} \,t^2\\x_f-x_i=17.3\,(1.88)-4.59\,(1.88)^2\\x_f-x_i=16.3\,ft

So, the maximum amount of time the ranger has to react and press the break while driving at 17.3 ft/s is the time to cover 242 ft minus 16.3 ft = 225.7 ft

During 225.7 ft the ranger could be driving in uniform motion (with speed 17.3 ft per second), we find the time to cover such:

x_f-x_i=v_i\,t\\225.7 = 17.3\,t\\t= \frac{225.7}{17.3} \\t\approx 13\, seconds

You might be interested in
If an object's velocity changes from 25 meters per second to
damaskus [11]

Answer:

B

Explanation:

the way to get b you have divion each other

3 0
2 years ago
Read 2 more answers
g In 1956, Frank Lloyd Wright proposed the construction of a mile-high building in Chicago. Suppose the building had been constr
Lorico [155]

To solve this problem it is necessary to apply the concepts related to acceleration due to gravity, as well as Newton's second law that describes the weight based on its mass and the acceleration of the celestial body on which it depends.

In other words the acceleration can be described as

a = \frac{GM}{r^2}

Where

G = Gravitational Universal Constant

M = Mass of Earth

r = Radius of Earth

This equation can be differentiated with respect to the radius of change, that is

\frac{da}{dr} = -2\frac{GM}{r^3}

da = -2\frac{GM}{r^3}dr

At the same time since Newton's second law we know that:

F_w = ma

Where,

m = mass

a =Acceleration

From the previous value given for acceleration we have to

F_W = m (\frac{GM}{r^2} ) = 600N

Finally to find the change in weight it is necessary to differentiate the Force with respect to the acceleration, then:

dF_W = mda

dF_W = m(-2\frac{GM}{r^3}dr)

dF_W = -2(m\frac{GM}{r^2})(\frac{dr}{r})

dF_W = -2F_W(\frac{dr}{r})

But we know that the total weight (F_W) is equivalent to 600N, and that the change during each mile in kilometers is 1.6km or 1600m therefore:

dF_W = -2(600)(\frac{1.6*10^3}{6.37*10^6})

dF_W = -0.3N

Therefore there is a weight loss of 0.3N every kilometer.

4 0
3 years ago
What happens to light when it travels from air into water
spin [16.1K]

Answer:

Water is more dense than air. When water goes through a denser thing, the light is "bent" more towards the "normal" which is a straight, vertical line.

Follow me on  i n s t a g r a m, message me and I'll follow you back: ifaulkner24

8 0
2 years ago
The following are possible ways to express the quantity 0.391 (Give ALL correct answers, i.e., B, AC, BCD...) Note: 3.45E-8 is a
laiz [17]
To answer, evaluate the power of 10 in the given choices. If it is positve, move the decimal n places to the right. If it is negative, move the decimal n corresponding places to the left. From all the choices given, only the choices D, E, and F will give us the correct answer. 
4 0
3 years ago
;-; please help me....​
sineoko [7]
The answer is 24N. Since the body is moving with constant velocity all the forces must balance (equal & opposite)
5 0
3 years ago
Other questions:
  • Compare wave A with wave B correctly in relation to amplitude.
    11·1 answer
  • Answers for 13 are
    10·1 answer
  • Think back to the example in the Warm-Up: A business owner wants to open a restaurant, but many residents do not want a business
    7·1 answer
  • Characteristics sa Ancient art
    8·1 answer
  • A car is strapped to a rocket (combined mass = 661 kg), and its kinetic energy is 66,120 J.
    13·1 answer
  • Dynamics Newton's 1st & 2nd Laws
    13·1 answer
  • Someone pushes on a rock and measures the net force acting on it is 147 N and acceleration to be 7.5m/s2.What is the weight of t
    15·1 answer
  • What is the electric potential difference of 5cm from a point charge of -2.0µc
    5·1 answer
  • Which of the following describes a heat sink?
    14·1 answer
  • hii, just wondering how to solve this? it’s simple scientific notation but my brain just isn’t functioning today so it’s be help
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!