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andrew-mc [135]

2 years ago

6

A wheelbarrow is experiencing two forces. One is pushing 5 N to the east and the other 5 N in the exact opposite direction. What

must be true of the wheelbarrow's motion?

2 answers:

Tamiku [17]2 years ago

7 0

Answer:

its acceleration must be 0.

Explanation:

According the second Newton's law, the net force applied in a object is equal to the mass of the object multiplied by its acceleration:

$F_{net} =m.a$

In this case, the net force is

$F_{net}=5N-5N=0$

What makes sense since both forces have the same value and opposite directions.

Since the mass of the object can't be zero, the acceleration is the one that must be 0 in order fulfill the equation of the second newton's law.

Another option is that, since both forces are opposite, the wheelbarrow could be at rest. Though this is correct, this is not always true.

In conclusion, the only statement that always is true about the wheelbarrow's motion is that its acceleration must be 0.

mezya [45]2 years ago

4 0

Assuming no other forces are acting on the wheelbarrow, it must be stationary.

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In a Rutherford scattering experiment a target nucleus has a diameter of 1.34×10-14 m. The incoming α particle has a mass of 6.6

Rasek [7]

Answer:

E = 2.5 x 10⁻¹⁴ J

Explanation:

given,

diameter = 1.33 x 10⁻¹⁴ m

mass = 6.64 x 10⁻²⁷ kg

wavelength is equal to diameter

de broglie wavelength equal to diameter

$\lambda = \dfrac{h}{mv}$

$1.33 \times 10^{-14}= \dfrac{6.626 \times 10^{-34}}{6.64 \times 10^{-27}\times v}$

$v= \dfrac{6.626 \times 10^{-34}}{6.64 \times 10^{-27}\times 1.33 \times 10^{-14}}$

v = 7.5 x 10⁶ m/s

Kinetic energy is equal to

$E = \dfrac{1}{2}mv^2$

$E = \dfrac{1}{2}\times 6.64 \times 10^{-27}\times (7.5\times 10^6)^2$

E = 2.5 x 10⁻¹⁴ J

8 0

3 years ago

Mark and David are loading identical cement blocks onto David’s pickup truck. Mark lifts his block straight up from the ground t

Pepsi [2]

Answer:

b) true. The jobs are equal

Explanation:

The work on a body is the scalar product of the force applied by the distance traveled.

W = F. d

Work is a scalar, the work equation can be developed

W = F d cos θ

Where θ is the angle between force and displacement

Let's apply these conditions to the exercise

a) False, if we see the expression d cosT is the projection of the displacement in the direction of the force, so there may be several displacement, but its projection is always the same

b) true. The jobs are equal dx = d cosθ

c) False, because the force is equal and the projection of displacement is the same

d) False, knowledge of T is not necessary because the projection of displacement is always the same

e) False mass is not in the definition of work

5 0

3 years ago

A vacuum cleaner produces sound with a measured sound level of 75.0 dB. (a) What is the intensity of this sound in W/m2? W/m2 (b

jonny [76]

Answer:

Part a)

$I = 3.16 \times 10^{-5} W/m^2$

Part b)

$P_o = 0.162 Pa$

Explanation:

Part a)

Level of sound = 75 dB

now we know that

$L = 10 Log\frac{I}{I_0}$

here we know that

$I_0 = 10^{-12} W/m^2$

now we have

$75 = 10 Log(\frac{I}{10^{-12}})$

$I = 3.16 \times 10^{-5} W/m^2$

Part b)

Intensity of sound wave is given as

$I = \frac{1}{2}\rho A^2\omega^2 c$

here we know that

$A = \frac{P_o}{Bk}$

so we have

$I = \frac{1}{2}\rho(\frac{P_o}{Bk})^2\omega^2 c$

$I = \frac{1}{2}\rho P_o^2 \frac{c^3}{B^2}$

now we know

$\rho = 1.2 kg/m^3$

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$B = 1.4 \times 10^5 Pa$

now we have

$3.16 \times 10^{-5} = \frac{1}{2}(1.2)P_o^2\frac{340^3}{(1.4\times 10^5)^2}$

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3 years ago

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Taya2010 [7]

Answer:

CaCO₃ and
NaOH.

Explanation:

Polyatomic ions are ions that contain more than one atom in each one of the ions.

Ionic compounds are made of cations (positive ions) and anions (negative ion). By convention, the cation is written before the anion.

List the ions in each compound:

<h3>CaCO₃</h3>

Cation: $\rm Ca^{2+}$ ,

Anion: $\rm {CO_3}^{2-}$ .

$\rm Ca^{2+}$ is a monatomic ion for it contains only one atom in each ion.

$\rm {CO_3}^{2-}$ is a polyatomic ion for it contains four atoms (one C atom and three O atoms) in each ion.

<h3>NaF</h3>

Cation: $\rm Na^{+}$ ,

Anion: $\rm F^{-}$ .

Both $\rm Na^{+}$ and $\rm F^{-}$ are monatomic for they contain only one atom in each ion.

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Cation: $\rm Fe^{2+}$ ,

Anion: $\rm {O}^{2-}$ .

Both $\rm Fe^{2+}$ and $\rm O^{2-}$ are monatomic for they contain only one atom in each ion.

<h3>CaCl₂</h3>

Cation: $\rm Ca^{2+}$ ,

Anion: $\rm {Cl}^{-}$ .

Both $\rm Ca^{2+}$ and $\rm Cl^{-}$ are monatomic for they contain only one atom in each ion.

<h3>NaOH</h3>

Cation: $\rm Na^{+}$ ,

Anion: $\rm {OH}^{-}$ .

$\rm Na^{+}$ is a monatomic ion for it contains only one atom in each ion.

$\rm {OH}^{-}$ is a polyatomic ion for it contains two atoms (one O atom and one H atom) in each ion.

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