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
slava [35]
3 years ago
10

A car is 200 m from a stop sign and traveling toward the sign at 40.0 m/s. At this time, the driver suddenly realizes that she m

ust stop the car. If it takes 0.200 s for the driver to apply the brakes, what must be the magnitude of the constant acceleration of the car after the brakes are applied so that the car will come to rest at the stop sign? A car is 200 m from a stop sign and traveling toward the sign at 40.0 m/s. At this time, the driver suddenly realizes that she must stop the car. If it takes 0.200 s for the driver to apply the brakes, what must be the magnitude of the constant acceleration of the car after the brakes are applied so that the car will come to rest at the stop sign? 3.89 m/s2 4.17 m/s2 2.89 m/s2 3.42 m/s2 2.08 m/s2
Physics
1 answer:
Zinaida [17]3 years ago
6 0

Answer:

4.17 m/s²

Explanation:

We are told the reaction time is 0.2 s. Now, during this reaction time the car is going to travel an additional distance of : x = u × t = 40 × 0.2 = 8 m

where u is the initial velocity of the car which is 40.0 m/s.

We are told that he had 200 m to stop before applying brakes. Thus, after applying brakes, he now has a distance to cover of; s = 200 - 8 = 192 m

Since vehicle is coming to rest acceleration would be negative, thus using Newton's equation of motion, we have;

v ² = u² - 2as

v = 0 m/s since it's coming to rest

u = 40 m/s

s = 192 m

Thus;

0² = 40² - 2(a)(192)

0² = 1600 - 384a

a = 1600/384

a = 4.17 m/s²

You might be interested in
Two positive charges q1 = q2 = 2.0 μC are located at x = 0, y = 0.30 m and x = 0, y = -0.30 m, respectively. Third point charge
Wittaler [7]

Answer:

 F = 0.111015 N

Explanation:

For this exercise the force is given by Coulomb's law

        F = k q₁q₂ / r₂₁²

we calculate the electric force of the other two particles on the charge q1

Charges q₁ and q₂

the distance between them is

          r₁₂ = y₁ -y₂

          r₁₂ = 0.30 + 0.30

          r₁₂ = 0.60 m

let's calculate

          F₁₂ = 9 10⁹ 2 10⁻⁶ 2 10⁻⁶ / 0.60 2

          F₁₂ = 1 10⁻¹ N

directed towards the positive side of the y-axis

Charges 1 and 3

Let's find the distance using the Pythagorean Theorem

             r₁₃ = RA [(0.40-0) 2 + (0-0.30) 2]

             r₁₃ = 0.50 m

            F₁₃ = 9 10⁹ 2 10⁻⁶ 4 10⁻⁶ / 0.50²

            F₁₃ = 1.697 10⁻² N

The direction of this force is on the line that joins the two charges (1 and 3), let's use trigonometry to find the components of this force

           tan θ = y / x

           θ = tan⁻¹ y / x

          θ = tan⁻¹ 0.3 / 0.4

           tea = 36.87º

    The angle from the positive side of the x-axis is

         θ ’= 180 - θ

        θ ’= 180 - 36.87

        θ ’= 143.13º

       sin143.13 = F_13y / F₁₃

           F_13y = F₁₃ sin 143.13

           F{13y} = 1.697 10⁻² sin 143.13

           F_13y = 1.0183 10⁻² N

            cos 143.13 = F_13x / F₁₃

           F₁₃ₓ = F₁₃ cos 143.13

           F₁₃ₓ = 1.697 10⁻² cos 143.13

           F₁₃ₓ = -1.357 10-2 N

Now we can find the components of the resultant force

          Fx = F13x + F12x

          Fx = -1,357 10-2 +0

          Fx = -1.357 10-2 N

          Fy = F13y + F12y

         Fy = 1.0183 10-2 + ​​1 10-1

          Fy = 0.110183 N

We use the Pythagorean theorem to find the modulus

         F = Ra (Fx2 + Fy2)

         F = RA [(1.357 10-2) 2 + 0.110183 2]

         F = 0.111015 N

Let's use trigonometry for the angles

         tan tea = Fy / Fx

          tea = tan-1 (0.110183 / -0.01357)

          tea = 1,448 rad

to find the angle about the positive side of the + x axis

           tea '= pi - 1,448

           Tea = 1.6936 rad

6 0
3 years ago
When we look at a star
stiv31 [10]

I'm not really sure what specific answer they're looking for, but if it's an open-ended question, then let's think about it this way...

A light year, is the distance it takes for light to travel in a year. If an object is 50,000 light years away, then by the time the light travels to us, 50,000 years has passed. We are looking at a 50,000 year old image of that object. (ignoring gravity and spatial expansion fun stuffs)

4 0
3 years ago
Which could describe the motion of an object?
Volgvan

mhm mhmhmhmhmmhmhmmh

3 0
3 years ago
Read 2 more answers
How fast should a moving clock travel if it is to be observed by a stationary observer as running at one-half its normal rate?A)
Elan Coil [88]

Answer:

Option (D) is correct.

Explanation:

Let the speed is v.

\Delta t = \gamma \Delta t'\\\\\Delta t = \frac{1}{\sqrt{1-\frac{v^2}{c^2}}}\times \frac{\Delta t}{2}\\\\\sqrt{1-\frac{v^2}{c^2}} =\frac{1}{2}\\\\1-\frac{v^2}{c^2}=\frac{1}{4}\\\\\frac{3}{4}c^2 = v^2\\\\v = 0.87 c

Option (D) is correct.

4 0
3 years ago
An engineer weighs a sample of mercury (ρ = 13.6 × 103 kg/m3 ) and finds that the weight of the sample is 6.0 n. what is the sam
Amanda [17]
Given:
ρ = 13.6 x 10³ kg/m³, density of mercury
W = 6.0 N, weight of the mercury sample
g = 9.81 m/s², acceleration due to gravity.

Let V =  the volume of the sample.
Then
W = ρVg
or
V =  W/(ρg)
   = (6.0 N)/[(13.6 x 10³ kg/m³)*(9.81 m/s²)]
   = 4.4972 x 10⁻⁵ m³

Answer: The volume is 44.972 x 10⁻⁶ m³
5 0
3 years ago
Other questions:
  • Of these choices, where would the most reactive nonmetal on the periodic table be located?
    13·2 answers
  • You are loading a toy dart gun, which has two settings, the more powerful with the spring compressed twice as far as the lower s
    7·1 answer
  • An electric motor does 900j of work for 8 hours. Calculate the power used​
    10·1 answer
  • The force of attraction between a -165.0 uC and +115.0 C charge is 6.00 N. What is the separation between these two charges in m
    9·1 answer
  • What are the two opposing forces at work as fusion takes place in stars?
    15·1 answer
  • Explain what parallel medium boundaries do to the path of the wave after it travels through both boundaries. (air and water)
    12·1 answer
  • În ce raport de mase trebuie amestecate două cantități din același lichid, având temperaturile t1=10 grade Celsius, respectiv t2
    10·1 answer
  • Mixed powders may be categorized as​
    9·1 answer
  • Which scientific law states the relationship between an object's mass, acceleration, and amount of force acting on it? (3 points
    14·2 answers
  • The data points you have taken on your lab graphs roughly form a straight line. How do you interpret the slope of this line?
    12·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!