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sukhopar [10]
3 years ago
13

They will only see the door move when both people exert the same force so that the forces are unbalanced. neither person exerts

a force on the door so that the net force is zero. one person exerts more force than the other so that the forces are unbalanced. both people exert the same force so that the forces are balanced.
Physics
1 answer:
Veseljchak [2.6K]3 years ago
5 0

Answer:

The correct answer is when one person exerts more force than the other so that the forces are unbalanced.

Explanation:

In fact, the door is initially at rest. In order to move the door, a net force different from zero should be applied, according to Newton's second law:

                                       <em> ∑F = ma</em>

where the term on the left is the resultant of the forces acting on the door, m is the door mass and a its acceleration. In order to move the door, the acceleration must be different from zero. But this means that the resultant of the forces acting on it must be different from zero: this is possible only if  the forces applied by the two persons are unbalanced, i.e. one person exerts more force than the other.

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A force of 44 N will stretch a rubber band 88 cm ​(0.080.08 ​m). Assuming that​ Hooke's law​ applies, how far will aa 11​-N forc
Setler79 [48]

Answer:

<em>The rubber band will be stretched 0.02 m.</em>

<em>The work done in stretching is 0.11 J.</em>

Explanation:

Force 1 = 44 N

extension of rubber band = 0.080 m

Force 2 = 11 N

extension = ?

According to Hooke's Law, force applied is proportional to the extension provided elastic limit is not extended.

F = ke

where k = constant of elasticity

e = extension of the material

F = force applied.

For the first case,

44 = 0.080K

K = 44/0.080 = 550 N/m

For the second situation involving the same rubber band

Force = 11 N

e = 550 N/m

11 = 550e

extension e = 11/550 = <em>0.02 m</em>

<em>The work done to stretch the rubber band this far is equal to the potential energy stored within the rubber due to the stretch</em>. This is in line with energy conservation.

potential energy stored = \frac{1}{2}ke^{2}

==> \frac{1}{2}* 550* 0.02^{2} = <em>0.11 J</em>

3 0
3 years ago
Please help me
Helen [10]

Answer:

15 protons and 18 electrons

General Formulas and Concepts:

<u>Chemistry</u>

  • Reading a Periodic Table
  • Element Number
  • Neutral Atoms
  • Ions

Explanation:

We are given the element P. P is 15 on the Periodic Table, meaning it has 15 protons and 15 electrons (all elements are in neutral form).

P³⁻ ion means the element now has a negative charge of 3. We know protons have a positive charge and electrons have a negative charge. 3- means we will have more electrons than protons.

Therefore, P³⁻ would have 15 protons and <em>18</em> electrons:

15 (+) + 18 (-) = 3 (-)

7 0
3 years ago
Read 2 more answers
A projectile rolls off a cliff with a velocity of 40 m/s. The cliff is 60 meters high.
masya89 [10]

Answer:

1) t = 3.45 s, 2)  x = 138 m, 3) v_{y} = -33.81 m /s, 4) v = 52.37 m / s ,

5) θ = -40.2º

Explanation:

This is a projectile exercise, as they indicate that the projectile rolls down the cliff, it goes with a horizontal speed when leaving the cliff, therefore the speed is v₀ₓ = 40 m / s.

1) Let's calculate the time that Taardaen reaches the bottom, we place the reference system at the bottom of the cliff

      y = y₀ + v_{oy} t - ½ g t²

When leaving the cliff the speed is horizontal  v_{oy}= 0 and at the bottom of the cliff y = 0

      0 = y₀ - ½ g t2

      t = √ 2y₀ / g

      t = √ (2 60 / 9.8)

      t = 3.45 s

2) The horizontal distance traveled

     x = v₀ₓ t

     x = 40 3.45

     x = 138 m

3) The vertical velocity at the point of impact

     v_{y} = I go - g t

     v_{y} = 0 - 9.8 3.45

     v_{y} = -33.81 m /s

the negative sign indicates that the speed is down

4) the resulting velocity at this point

   v = √ (vₓ² + v_{y}²)

   v = √ (40² + 33.8²)

   v = 52.37 m / s

5) angle of impact

    tan θ = v_{y} / vx

    θ = tan⁻¹ v_{y} / vx

    θ = tan⁻¹ (-33.81 / 40)

    θ = -40.2º

6) sin (-40.2) = -0.6455

7) tan (-40.2) = -0.845

8) when the projectile falls down the cliff, the horizontal speed remains constant and the vertical speed increases, therefore the resulting speed has a direction given by the angle that is measured clockwise from the x axis

6 0
3 years ago
Lagrangian mechanics. Determine the equations of motion for a particle of mass m constrained to move on the surface of a cone in
maria [59]

Answer:

Explanation:

Hi!

In order to obtain the Lagrangian of the system we must first write the Kinetic and Potential Energies. Lets orient our axes such that the axis of the cone coincide with the z axis. In cilindrical coordinates we have

v^{2} = \frac{dr}{dt}^{2}  +r^{2} \frac{d\theta }{dt} ^{2} +\frac{dz}{dt} ^{2} - (1)

But, since the particle is constrained to move on the surface of the cilinder, we have the following relation between r and z:

\frac{r}{z}=tan(45)

or:

z = r cot(45) - (2)

and:

\frac{dz}{dt} = \frac{dr}{dt} cot(45)

replacing (2) in (1) we obtain:

v^{2} = \frac{dr}{dt}^{2} (1+cot(45))+r^{2}\frac{d\theta }{dt} ^{2}  - (3)

Now the kinetic energy is given as:

T = \frac{1}{2}m(\frac{dr}{dt}^{2} (1+cot(45))+r^{2}\frac{d\theta }{dt} ^{2}) - (4)

And the potential energy is given by:

V = -mgz = -mgr cot(45)

So the Langrangian is given by:

L = T - V= \frac{1}{2}m(\frac{dr}{dt}^{2}(1+cot(45)+r^{2})\frac{d\theta }{dt} ^{2}) + mgr cot(45)

And the equations of motion are:

For θ

\frac{d}{dt} (mr\frac{d\theta}{dt}) = 0-->mr{d\theta}{dt}=c

For r

\frac{d}{dt}(m\frac{dr}{dt}(1+cot(45) )= mgcot(45)+mr\frac{d\theta}{dt} ^{2}\\m\frac{d^{2} r}{dt^{2} }(1+cot(45)= mgcot(45)+mr\frac{d\theta}{dt} ^{2}

Obtained from the Euler-Langrange equations

Here the conserved quantity is given by the first equation of motion, namely:

mr\frac{d\theta}{dt}=c

Which is the magnitude of the angular momentum

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3 years ago
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Y_Kistochka [10]

Answer:

A time period is denoted by 'T' . It is the time to complete one cycle of vibration. As the frequency of a wave increases, the time period of the wave decreases. The unit for time period is 'seconds

HOPE IT HELPS :)

PLEASE MARK  IT THE BRAINLIEST!

4 0
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