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
Yakvenalex [24]
3 years ago
8

A car slows down from speed of 72

Physics
1 answer:
Nastasia [14]3 years ago
5 0

Explanation:

Given parameters:

Initial velocity = 72km/hr

Final velocity  = 0km/hr

Time taken  = 25s

Unknown:

Acceleration = ?

Solution:

To solve this problem, convert km/hr to m/s;

           1000m = 1km

           3600s = 1hr

  72km/hr;

          1km/hr  = 0.278m/s

         72km/hr = 0.278 x 72  = 20.02m/s

Acceleration is the change in velocity divided by the time taken;

       Acceleration = \frac{final velocity - initial velocity }{time}  

       Acceleration  = \frac{0 - 20.02}{25}   = -0.8m/s

The car  is actually decelerating at a rate of 0.8m/s

You might be interested in
A copper rod of length 27.5 m has its temperature increases by 35.9 degrees celsius. how much does its length increase?(unit=m)
gavmur [86]
<h2>The increase in length = 1.87 x 10⁻²</h2>

Explanation:

When copper rod is heated , its length increases

The increase in length can be found by the relation

L = L₀ ( 1 + α ΔT )

here L is the increased length and L₀ is the original length

α  is the coefficient of linear expansion and ΔT is the increase in temperature .

The increase in length = L - L₀ = L₀ x α ΔT

Substituting all these value

Increase in length = 27.5 x 1.7 x 10⁻⁵ x 35.9

= 1.87 x 10⁻² m

5 0
3 years ago
Read 2 more answers
A wheel with moment of inertia 25 kg. m2 and angular velocity 10 rad/s begins to speed up, with angular acceleration 15 rad/sec2
Pani-rosa [81]

Answer:

(A) Angular speed 40 rad/sec

Rotation = 50 rad

(b) 37812.5 J

Explanation:

We have given moment of inertia of the wheel I=25kgm^2

Initial angular velocity of the wheel \omega _0=10rad/sec

Angular acceleration \alpha =15rad/sec^2

(a) We know that \omega =\omega _0+\alpha t

We have given t = 2 sec

So \omega =10+15\times  2=40rad/sec

Now \Theta =\omega _0t+\frac{1}{2}\alpha t^2=10\times 2+\frac{1}{2}\times 15\times 2^2=50rad

(b) After 3 sec \omega =10+15\times 3=55rad/sec

We know that kinetic energy is given by Ke=\frac{1}{2}I\omega ^2=\frac{1}{2}\times 25\times 55^2=37812.5J

7 0
3 years ago
A 120-kg roller coaster cart is being tested on a new track, and a crash-test dummy is loaded into it. The roller coaster starts
avanturin [10]

Answer:

vb = 22.13 m/s

So, the only thing that was measured here was the height of point A relative to point B. And the Law of Conservation of Energy was used.

Explanation:

In order to find the speed of roller coaster at Point B, we will use the law of conservation of Energy. In this situation, the law of conservation of energy states that:

K.E at A + P.E at A = K.E at B + P.E at B

(1/2)mvₐ² + mghₐ = (1/2)m(vb)² + mg(hb)

(1/2)vₙ² + ghₐ = (1/2)(vb)² + g(hb)

where,

vₙ = velocity of roller coaster at point a = 0 m/s

hₙ = height of roller coaster at point a = 25 m

g = 9.8 m/s²

vb = velocity of roller coaster at point B = ?

hb = Height of Point B = 0 m (since, point is the reference point)

Therefore,

(1/2)(0 m/s)² + (9.8 m/s²)(25 m) = (1/2)(vb)² + (9.8 m/s²)(0 m)

245 m²/s² * 2 = vb²

vb = √(490 m²/s²)

<u>vb = 22.13 m/s</u>

<u>So, the only thing that was measured here was the height of point A relative to point B. And the Law of Conservation of Energy was used.</u>

5 0
3 years ago
Explain Energy Transformation using the image below and how the Law of Conservation of Energy is maintained.
Karolina [17]

The chemical energy of petrol is converted to heat energy on combustion. The heat energy is converted to kinetic energy by the use of internal combustion engines in vehicles. The law of conservation of energy is maintained in each process.

<h3>What is kinetic energy?</h3>

The kinetic energy of an object is associated with its motion. It can be related to the mass and velocity as

K.E = 1/2 mv²

Given is a diagram of energy conversion due to combustion.

The chemical energy of petrol is converted to heat energy on combustion. The heat energy is converted to kinetic energy by the use of internal combustion engines in vehicles.

The law of conservation of energy states that the energy can neither be created nor destroyed. It can be only converted to one form to the other.

In the given process, the mass decreases but energy remains the same in all forms of energy.

Hence, the law of conservation of energy is maintained in each process

Learn more about kinetic energy.

brainly.com/question/12669551

#SPJ1

8 0
2 years ago
What is the frame of reference for a plane moving at 500 km/h?
RUDIKE [14]
The frame of reference is the rotating earth underneath the flight path of the plane, the rate of rotation of the earth is 1036 miles per hour, meaning that the pilot has to compensate this fact when landing the aircraft.
3 0
3 years ago
Read 2 more answers
Other questions:
  • A coil of conducting wire carries a current of i(t) = 14.0 sin(1.15 ✕ 103t), where i is in amperes and t is in seconds. A second
    8·1 answer
  • Why does a coastal area have less variation in temperature than a noncoastal area? Temperatures feel cool all year round due to
    14·2 answers
  • Which is not a common property of ionic compounds
    12·1 answer
  • Would you rather be beautiful but you cant look at yourself or be ugly and no one else can see you
    12·1 answer
  • Where do cells get the chemicals needed to synthesize other molecules?
    12·2 answers
  • Select the correct answer.
    14·1 answer
  • 10 points
    10·1 answer
  • How often should muscle strengthening activities be performed?
    11·2 answers
  • a car that is moving in a straight line has an acceleration of 8.0 m/s/s for 4.0 seconds. which one of the following is true of
    14·1 answer
  • The equation below can be used to calculate a change in gravitational potential energy. What units must be used for h? Give the
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!