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
katen-ka-za [31]
3 years ago
5

During a braking test, a car is brought to rest beginning from an initial speed of 60 mi/hr in a distance of 120 ft. With the sa

me constant deceleration, what would be the stopping distance s from an initial speed of 80 mi/hr?
Physics
1 answer:
maw [93]3 years ago
8 0

Answer:

Explanation:

Given

Initial speed u=60\ mi/hr\approx 88\ ft/s

distance traveled before coming to rest d_1=120\ ft

using equation of motion

v^2-u^2=2as

where v=final velocity

u=initial velocity

a=acceleration

s=displacement

0-(88)^2=2\times a\times 120---1

for u_2=80\ mi/hr\approx 117.33\ ft/s

using same relation we get

0-(117.33)^2=2\times a\times (d_2)----2

divide 1 and 2 we get

(\frac{88}{117.33})^2=\frac{120}{d_2}

d_2=213.32\ ft

So a distance if 213.32 ft is required to stop the vehicle with 80 mph speed

You might be interested in
A pencil rolls horizontally of a 1 meter high desk and lands .25 meters from the base of the desk. How fast was the pencil rolli
vovikov84 [41]

Answer: 0.55 m/s

Explanation:

This situation is related to projectile motion (also called parabolic motion), where the main equations are as follows:

x=V_{o} cos\theta t (1)

y=y_{o}+Vo sin \theta t + \frac{g}{2}t^{2} (2)

Where:

x=0.25 m is the horizontal displacement of the pencil

V_{o} is the pencil's initial velocity

\theta=0\° since we are told the pencil rolls <u>horizontally</u> before falling

t is the time since the pencil falls until it hits the ground

y_{o}=1 m  is the initial height of the pencil

y=0  is the final height of the pencil (when it finally hits the ground)

g=-9.8m/s^{2}  is the acceleration due gravity, always acting vertically downwards

Begining with (1):

x=V_{o} cos(0\°) t (3)

x=V_{o}t (4)

Finding t from (2):

0=1 m+ \frac{-9.8m/s^{2}}{2}t^{2} (5)

t=\sqrt{\frac{-2y_{o}}{g}} (6)

Substituting (6) in (4):

x=V_{o}\sqrt{\frac{-2y_{o}}{g}} (7)

Isolating V_{o}:

V_{o}=\frac{x}{\sqrt{\frac{-2y_{o}}{g}}} (8)

V_{o}=\frac{0.25 m}{\sqrt{\frac{-2(1 m)}{-9.8m/s^{2}}}} (9)

Finally:

V_{o}=0.55 m/s

4 0
3 years ago
Select the correct answer.
Morgarella [4.7K]
D all of them is the answer. All three can be used to celebrate sporting events
3 0
2 years ago
How much conventional current must you run in a solenoid with radius = 0.05 m and length = 0.39 m to produce a magnetic field in
Ugo [173]

Answer:

Explanation:

radius of the solenoid, r = 0.05 m

length of the solenoid, l = 0.39 m

Magnetic field of the solenoid, B = 2 x 10^-5 T

Number of turns, N = 200

The magnetic field of the solenoid is given by

B=\mu _{0}ni

where, i be the current and n be the number of turns per unit length

n = N / l = 200 / 0.39 = 512.8

2\times 10^{-5}=4 \times 3.14\times 10^{-7}\times 512.8\times i

i = 0.031 A

3 0
3 years ago
Why does it takes a long time to heat a room with a high ceiling?
vlada-n [284]

Answer:

High ceilings make a room feel large and open, but they can be difficult to cool and heat. Because hot air rises, the challenge becomes trying to keep the hot air where you want it and preventing if from being wasted where you don't.

Explanation:

:)

6 0
3 years ago
Read 2 more answers
Assume you are given an int variable named nElements and a two-dimensional array that has been created and assigned to a2d. Writ
Alex777 [14]

Answer:

Explained

Explanation:

public int dimension(int [][]a2d,int nElements)

{

int count = 0;

for(int i = 0;i < a2d.length ; i++)

{

count = count + a2d[i].length;

}

return count;

}

3 0
3 years ago
Other questions:
  • How does south African law ensure that people who are living with HIV/AIDS are not discriminated against
    11·1 answer
  • Which is a common cause of incomplete combustion
    6·2 answers
  • The answer pleaseeeeeee
    9·1 answer
  • I need the answer for this question
    5·1 answer
  • A marshmallow in a vacuum becomes <br><br> A) larger. <br> B) smaller. <br> C) does not change.
    12·2 answers
  • PLEASE HELP WITH THIS QUESTION<br><br>What of Newton's 3 laws is this picture​
    7·1 answer
  • Determine the amount of work you would need to do in order to stop a 1100kg car with 1400J of kinetic energy.
    9·1 answer
  • In a simple 2-bulb series circuit, why does the bulb light when you close the switch?
    10·1 answer
  • Question 2 of 5
    7·1 answer
  • Do you know what NBA basketball player is this. And what is he doing to stay healthy.
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!