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
Sveta_85 [38]
3 years ago
13

At an accident scene on a level road, investigators measure a car's skid mark to be 93 m long. It was a rainy day and the coeffi

cient of friction was estimated to be 0.35. Use these data to determine the speed of the car when the driver slammed on (and locked) the brakes. Express your answer to two significant figures and include the appropriate units
Physics
1 answer:
USPshnik [31]3 years ago
6 0

Answer:

u = 25 m/s

Explanation:

given,                                

length of skid = 93 m          

coefficient of friction = 0.35

final velocity = 0 m/s              

initial velocity = ?                        

force here is friction  f = μ mg

F = ma                                                

now com paring                      

-μ mg = m a                      

a = - μ g                    

a = - 0.35 x 9.8              

a = -3.43 m/s²

we know,              

v² = u² + 2 a s                        

0 = u² - 2 x 3.43 x 93                

u² = 637.98                    

u = 25.26 m/s                      

u = 25 m/s (two significant figure)

You might be interested in
One property that makes electromagnetic waves differ from other types of waves is that they can
IgorC [24]
Electromagnectic Waves Travel In A Vacuum
4 0
3 years ago
Read 2 more answers
Which phase of matter does not conduct heat well?
inessss [21]
Gases do not conduct heat well. 
4 0
3 years ago
Read 2 more answers
Some one help my science homework is due tomorrow and I'm so stuck with question 8-9, and 11-12
yuradex [85]
Off the top of my head, I only know 9 and 11, so I'll answer those two.

9) A heterotroph is an organism that relies on other organisms for food/energy
    An autotroph can produce its own food from inorganic compounds (light)

11) Vascular plants have specialized tubes for transporting nutrients
      Nonvascular plants do not have such tubes and are simpler
5 0
3 years ago
In one cycle, a heat engine takes in 1000 J of heat from a high-temperature reservoir, releases 600 J of heat to a lower-tempera
Talja [164]

Answer:

η = 40 %  

Explanation:

Given that

Qa ,Heat addition= 1000  J

Qr,Heat rejection= 600 J

Work done ,W= 400 J

We know that ,efficiency of a engine given as

\eta=\dfrac{W(net)}{Q(heat\ addition)}

Now by putting the values in the above equation ,then we get

\eta=\dfrac{400}{1000}

η = 0.4

The efficiency in percentage is given as

η = 0.4  x 100 %

η = 40 %

Therefore the answer will be 40%.

4 0
3 years ago
A solid, homogeneous sphere with a mass of m0, a radius of r0 and a density of rho0 is placed in a container of water. Initially
ivanzaharov [21]

Answer:

a) s,f,r  b) r c) f

Explanation:

To determine what happens with the sphere we use Newton's second law with the Archimedes principle that states that the thrust (B) on a body is equal to the weight of the liquid dislodged

For the sphere to be in equilibrium the sum of forces is zero

    B - W = 0

    B = W = mg

Now let's use the concept of density for the body and water

Solid sphere

   ρ = m / V

  V = 4/3 π r³

   m = ρ₀ (4/3 π r³)

   W = ρ₀ (4/3 π r³) g

Water  (a)

   ρ = mₐ / Vₐ

   mₐ = ρ Vₐ

   B = ρ Vₐ g

Let's replace and simplify

   ρ Vₐ g = ρ₀ (4/3 π r³) g

    ρ Vf = ρ₀ (4/3 π r³)            (1)

For the initial condition with rho, mo and ro the height of the water is H, let's analyze each case

a) We have the same mass, but less radius, as density is mass over volume density increases

   r  <ro        V <V₀   ⇒      ρ₁> ρ₀

When analyzing the equation (1) on the right side, this case is the most complicated because I can make the relationship between the density of the sphere and its volume change even when the mass is constant

Assume the three possibilities

- The product of (ρ₁ V) that does not matter in that case the left side does not change and the mark remains the same (s)

- The product (ρ₁ V) increases the left side must increase so the mark goes up (r)

- The product (ρ₁ V) decreases the left side should go down, so the low mark (f)

b) sphere the same radius, but the density increases.

In this case the right side of the equation (1) increases, therefore the left side must increase so that the volume must increase and consequently increase the height (r)

c) you have the same radius, but the mass decreases

      r = r₀     V = V₀     m <m₀        ρ₁ <ρ₀

The right side of the equation decreases, because the density decreases, the left side must decrease, for this the volume must decrease, lowering the height (f)

8 0
3 years ago
Other questions:
  • "two planets have the same mass, but planet a has 3 times the radius of planet
    15·1 answer
  • In a loop-the-loop ride a car goes around a vertical, circular loop at a constant speed. The car has a mass m = 268 kg and moves
    11·1 answer
  • A person of mass 75 kg stands at the center of a rotating merry-go-round platform of radius 3.3 m and moment of inertia
    13·1 answer
  • Two carts, one of mass 2m and one of mass m, approach each other with the same speed, v. When the carts collide, they
    10·1 answer
  • WILL GIVE BRAINLIEST ANSWER!!!!!!!!!!!!!!!!!!!!!!!!! ITS WORTH 99 POINTS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    11·2 answers
  • If the change in position Dx is related to velocity v (with units of m/s) in the equation Dx=Av, the constant A has which dimens
    6·1 answer
  • Carter pushes a bag full of basketball jerseys across the gym floor. The he pushes with a constant force of 21 newtons. If he pu
    8·2 answers
  • A plane is traveling at 300 m/s. How far will it travelin 1 hour?
    9·1 answer
  • Which of the following is same dimension quantity?
    15·1 answer
  • The kinetic energy of an object can sometimes be greater than a potential energy a originally possessed, true or false?
    7·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!