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horsena [70]
3 years ago
10

A car accelerates at 3 m/s*2. Assuming the car starts from rest, how much time does it need to

Physics
2 answers:
Eduardwww [97]3 years ago
6 0

We are given with some parameters used in Kinematics for determining the motion of an object.

  • Accleration = 3 m/s²
  • Started from rest (Initial vel.) = 0 m/s
  • Final velocity = 12 m/s

We have to find the time taken by the car to attain the final velocity with the given accleration. By using 1st equation of motion which says:

  • v = u + at

Final velocity = Initial velocity + Accl. × Time taken

Plugging the values,

➝ 12 = 0 + 3(t)

➝ 3t = 12

➝ t = 4 s

So, the correct answer is Option C. And we are done...

Carry On Learning !

uranmaximum [27]3 years ago
5 0
<h3><u>Given</u><u>:</u><u>-</u></h3>

Acceleration,a = 3 m/s²

Initial velocity,u = 0 m/s

Final velocity,v = 12 m/s

<h3><u>To</u><u> </u><u>be</u><u> </u><u>calculated:-</u><u> </u></h3>

Calculate the time take by a car.

<h3><u>Solution:-</u><u> </u></h3>

According to the first equation of motion:

v = u + at

★ Substituting the values in the above formula,we get:

⇒ 12 = 0 + 3 × t

⇒ 12 = 3t

⇒ 3t = 12

⇒ t = 12/3

⇒ t = 4 sec

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A projectile is launched vertically at 100 m/s. If air resistance can be ignored, at what speed will it return to its initial le
eduard
<h2>Speed with which it return to its initial level is 100 m/s</h2>

Explanation:

We have equation of motion v² = u² + 2as

Initial velocity, u = 100 m/s  

Acceleration, a = -9.81 m/s²  

Final velocity, v = ?

Displacement, s = 0 m  

Substituting  

v² = u² + 2as

v² = 100² + 2 x -9.81 x 0

v² = 100²

v = ±100 m/s

+100 m/s is initial velocity and -100 m/s is final velocity.

Speed with which it return to its initial level is 100 m/s

7 0
3 years ago
Read 2 more answers
A woman pushes an oak chest across an oak floor at a constant speed of 0.450 m/s. The chest has a mass of 40.0 kg, and the coeff
natima [27]

Answer:

A. 243 N

Explanation:

Friction is the force that opposes the relative motion between systems that are in contact.

This friction force that opposes the motion of the oak chest across the oak surface will be equal and opposite to that exerted by the woman.

First find the normal force which is the force that would point directly upwards to support weight of the block.

Normal force, N= mg where m is the mass of the chest and g is the acceleration due to gravity.

Given m=40 kg and g=9.80 m/s²

N force=40×9.80 =392N

Then find the force of friction which is given by the formula;

<em>F=μN where μ is friction coefficient for the  oak chest  and N is the normal force on the chest</em>

Given <em>μ</em>=0.620  and N force = 392 N then it will be;

F=0.620× 392 =243.04 N

Answer : 243 N

6 0
3 years ago
Which interactions are part of the greenhouse effect? Select three options.
Allisa [31]

<u>Out of the given options, the following interactions are part of the greenhouse effect, </u>

  • Gases in the atmosphere absorb heat
  • Earth’s surface radiates energy back into the atmosphere
  • Gases in the atmosphere radiate heat back to the surface

Answers: Options A, D and E

<u>Explanation: </u>

The greenhouse effect, basically a warming effect caused by the greenhouse gases such as Carbon-Di-oxide, Methane, nitrous oxides, water vapour etc. These gases usually trap the heat that Earth Absorbs by the Sun.  

In the day time, the Earth absorbs the energy in the form of heat which is radiated by the Sun. In the evening, the process gets reversed and the Earth starts releasing that heat into the atmosphere.

Now, this heat gets absorbed by this gases before it leaves the Earth's atmosphere and gets trapped there only, resulting in the temperature raise of the Earth's environment.

So, the prime causes of the greenhouse effect remains as the heat radiation from the Sun, the absorption of that heat by the Earth surface and the further absorption of that heat produced by the greenhouse gases that present in the atmosphere.

5 0
3 years ago
Read 2 more answers
Your friend decides to generate electrical power by rotating a 100,000 turn coil of wire around an axis in the plane of the coil
MakcuM [25]

Answer:

a) I=35mA

b) P=1.73W

Explanation:

a) The max emf obtained in a rotating coil of N turns is given by:

emf_{max}=NBA\omega

where N is the number of turns in the coil, B is the magnitude of the magnetic field, A is the area and w is the angular velocity of the coil.

By calculating A and replacing in the formula (1G=10^{-4}T) we get:

A=\pi r^2 =\pi(0.23m)^2=0.16m^2

emf_{max}=(100000)(0.3*10^{-4}T)(0.166m^2)(140\frac{rev}{s})=69.72V

Finally, the peak current is given by:

I=\frac{emf}{R}=\frac{69.72V}{1400\Omega}=49.8mA

b)

we have that

I_{rms}=\frac{I}{\sqrt{2}}=\frac{0.0498A}{\sqrt{2}}=0.035A

P_{rms}=I^2{rms}R=(0.035A)^2(1400\Omega)=1.73W

hope this helps!!

6 0
3 years ago
Why is there convection in the outer core and what is the result of this?
mars1129 [50]

Answer:

re believed to influence the Earth's magnetic field. ... As heat is transferred outward toward the mantle, the net trend is for the inner boundary of the liquid region to freeze, causing the solid inner core to grow

Explanation:

6 0
3 years ago
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