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loris [4]
3 years ago
5

Beginning at time t = 0, a student exerts a horizontal force on a box of mass 30 kg, causing it to move at 1.2 m/s toward an ele

vator door located 16 m away, as shown above. the coefficient of kinetic friction k m between the box and the floor is 0.20.
Physics
1 answer:
Alexandra [31]3 years ago
6 0
Since the initial and the final velocity are just equal, it is implied that the acceleration is zero. This means that the net force acting on the body is also zero. The horizontal force should be equal to the force of friction. The force of friction is equal to the product of the coefficient and the normal force. 
                               

 Ff = (coefficient of friction) x Fn


The normal force is equal to the object's weight if the surface is horizontal.


                               Ff = (0.20) x (30 kg) x (9.8 m/s²)  = 58.8 N
<span>

<span>Thus, the horizontal force exerted must be 58.8 N. 

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I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!

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Answer:

False

Explanation:

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Using the equation of motion under freefall, s = ut +1/2gt². Since u = 0,

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3 years ago
A sailboat is traveling across the ocean with a speed of 4 m/s when large gusts of wind pick up that starts to accelerate the sa
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solution:

Using Cartesian co-ordinate system

Final velocity =v= -4m/s

Initial velocity = u

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Time (t).= 60s

By the first kinematical equation

V= u +at

U = v – at

=(-4)-(-3)(60)

176m/s

So, initial velocity was 176m/s


8 0
4 years ago
Astronomers discover an exoplanet, a planet obriting a star other than the Sun, that has an orbital period of 3.27 Earth years i
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Answer:

  r = 3.787 10¹¹ m

Explanation:

We can solve this exercise using Newton's second law, where force is the force of universal attraction and centripetal acceleration

    F = ma

    G m M / r² = m a

The centripetal acceleration is given by

    a = v² / r

For the case of an orbit the speed circulates (velocity module is constant), let's use the relationship

    v = d / t

The distance traveled Esla orbits, in a circle the distance is

    d = 2 π r

Time in time to complete the orbit, called period

     v = 2π r / T

Let's replace

    G m M / r² = m a

    G M / r² = (2π r / T)² / r

    G M / r² = 4π² r / T²

    G M T² = 4π² r3

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Let's reduce the magnitudes to the SI system

     T = 3.27 and (365 d / 1 y) (24 h / 1 day) (3600s / 1h)

     T = 1.03 10⁸ s

Let's calculate

      r = ∛[6.67 10⁻¹¹ 3.03 10³⁰ (1.03 10⁸) 2) / 4π²2]

      r = ∛ (21.44 10³⁵ / 39.478)

      r = ∛(0.0543087 10 36)

      r = 0.3787 10¹² m

      r = 3.787 10¹¹ m

7 0
3 years ago
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Answer:Explained

Explanation:

The scientist of that time could not believe that the electromagnetic waves do not require a medium to travel through so they made a space filling substance necessary to travel of electromagnetic waves called aether.

But after the special 0 theory of relativity this idea is discarded and fell out.

6 0
3 years ago
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