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
WARRIOR [948]
3 years ago
12

A car traveling at a speed of 30.0 m/s encounters an emergency and comes to a complete stop. how much time will it take for the

car to stop if it decelerates at -4.0 m/s2
Physics
1 answer:
Vedmedyk [2.9K]3 years ago
8 0

Answer:7.5seconds

Explanation:

V=0 u=30m/s a=-4m/s^2

t=(v-u)/a

t=(0-30)/-4=-30/-4

t=7.5second

You might be interested in
Sketch a reaction progress curve for a reaction that has an activation energy of 22 kj and the total energy change is -103kj.
crimeas [40]

Answer:

Do find the answer in the attachment herein.

Explanation:

From the attached diagram:

I. Activation energy = Activated complex - ∆H(reactants)

Activation energy = 162-140 = 22Kj.

II. ∆H(reaction) = ∆H(products) - ∆H(reactants)

∆H(reaction) = 37 - 140 = -103Kj.

8 0
3 years ago
In order to be considered a semi-conductor the material must
wel
First one, for instance they become conductors or insulators depending on the temperature!
4 0
4 years ago
Read 2 more answers
Why does a hot-air balloon rise?
prohojiy [21]

Answer: The weight of the air displaced by the balloon is less than the volume of the balloon.

Explanation:

A hot air balloon is a cloth wrap that contains several thousand cubic meters of air inside (a large volume of air). The burner heats the liquid propane to a gaseous state to generate a huge flame, which can reach more than 3 meters, thus heating the air mass inside the balloon. In this way,<u> its density is modified with respect to the air that surrounds it</u>, because the hot air is lighter than the outside air (less dense), causing the balloon to rise and float.

Now, if we know that the density of a body d is directly proportional to its mass m and inversely proportional to its volume V:

d=\frac{m}{V}

We can deduce that <u>by increasing the volume of the body, its density will decrease.</u>

This is proof of <em><u>Archimedes' Principle</u></em>:  

<em>A body totally or partially immersed in a fluid at rest, experiences a vertical upward thrust equal to the mass weight of the body volume that is displaced.</em>

In this case the fluid is the air outside. So, the warm air inside the balloon, being less dense, will weigh less than the outside air and therefore will receive an upward pushing force or thrust that will make the balloon ascend.

4 0
3 years ago
Cynthia forgot to put the fabric softener in the wash. As her socks tumbled in the dryer, they became charged. If a small piece
polet [3.4K]

Answer:

E = 24000 N/C = 24 KN/C

Explanation:

The electric field experienced by a test charge is given by the following formula:

E = \frac{F}{q}\\\\

where,

E = Electric Field = ?

F = Force of attraction = 3 x 10⁻⁶ N

q = Charge on piece of lint = 1.25 x 10⁻¹⁰ C

Therefore, using these values in the equation, we get:

E = \frac{3\ x\ 10^{-6}\ N}{1.25\ x\ ^{-10}\ C}\\\\

<u>E = 24000 N/C = 24 KN/C</u>

6 0
3 years ago
Unpolarized light with an average intensity of 845 W/m2 enters a polarizer with a vertical transmission axis. The transmitted li
RideAnS [48]

The concept to develop this problem is the Law of Malus. Which describes what happens with the light intensity once it passes through a polarized material.

Mathematically this can be expressed as

I = I_0 cos^2\theta

Where

I = New intensity after pass through the Polarizer

I_0= Original intensity

\theta = Indicates the angle between the axis of the analyzer and the polarization axis of the incident light.

When the light passes perpendicularly through the first polarizer, the light intensity is reduced by half which will cause the intensity to be 225W / m ^ 2 at the output of the new polarizer, mathematically:

I= \frac{I_0}{2} cos^2\theta

225 = \frac{845}{2}cos^2\theta

Solving to find the angle we have

\theta = 43.11\°

The orientation angle of the second polarizer relative to the first one is 43.11°

5 0
3 years ago
Other questions:
  • A motor vehicle has a mass of 1.8 tonnes and its wheelbase is 3 m. The centre of gravity of the vehicle is situated in the centr
    14·1 answer
  • What does the force diagram look like for a book at rest on a desk?
    8·1 answer
  • IS magnesium lactate a strong or weak electrolyte
    5·1 answer
  • A diffusion couple of two metals, A and B, was fashioned as shown in Figure 5.1. After a 26 hour heat treatment at 1050°C (and s
    7·1 answer
  • A climber using bottled oxygen accidentally drops the oxygen bottle from an altitude of 4500 m. If the bottle fell straight down
    13·1 answer
  • One might imagine that if energy generation by nuclear fusion were to increase in a star, this would heat the gas, which would i
    9·1 answer
  • Suppose a point charge is located at the center of a spherical surface. The electric field at the surface of the sphere and the
    13·1 answer
  • Which is a device made from a coil of wire that carries a current and produces a magnetic field?
    8·2 answers
  • In a football game, running back is at the 10 yard line and running up the field towards the 50 yard line, and runs for 3 second
    5·1 answer
  • According to evidence presented in both the text and video, which statement is the most accurate regarding the relationship betw
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!