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nlexa [21]
3 years ago
11

3. A 2kg wooden block whose initial speed is 3 m/s slides on a smooth floor for 2 meters before it comes to a

Physics
1 answer:
serious [3.7K]3 years ago
7 0

Answer:

Calculating Coefficient of friction is 0.229.

Force is 4.5 N that keep the block moving at a constant speed.

Explanation:

We know that speed expression is as \mathrm{V}^{2}=\mathrm{V}_{\mathrm{i}}^{2}+2 . \mathrm{a} . \Delta \mathrm{s}.

Where, {V}_{i} is initial speed, V is final speed, ∆s displacement and a acceleration.

Given that,

{V}_{i} =3 m/s, V = 0 m/s, and  ∆s = 2 m

Substitute the values in the above formula,

0=3^{2}-2 \times 2 \times a

0 = 9 - 4a

4a = 9

a=2.25 \mathrm{m} / \mathrm{s}^{2}

a=2.25 \mathrm{m} / \mathrm{s}^{2} is the acceleration.

Calculating Coefficient of friction:

\mathrm{F}=\mathrm{m} \times \mathrm{a}

\mathrm{F}=\mu \times \mathrm{m} \times \mathrm{g}

Compare the above equation

\mu \times m \times g=m \times a

Cancel "m" common term in both L.H.S and R.H.S

\text { Equation becomes, } \mu \times g=a

\text { Coefficient of friction } \mu=\frac{a}{g}

\mathrm{g} \text { on earth surface }=9.8 \mathrm{m} / \mathrm{s}^{2}

\mu=\frac{2.25}{9.8}

\mu=0.229

Hence coefficient of friction is 0.229.

calculating force:

\text { We know that } \mathrm{F}=\mathrm{m} \times \mathrm{a}

\mathrm{F}=2 \times 2.25 \quad(\mathrm{m}=2 \mathrm{kg} \text { given })

F = 4.5 N

Therefore, the force would be <u>4.5 N</u> to keep the block moving at a constant speed across the floor.

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Dimas [21]

An object's momentum is the product of its mass and its velocity:

p = mv

p is its momentum, m is its mass, and v is its velocity.

Given values:

p = -80kg×m/s

m = 8kg

Plug in these values and solve for v:

-80 = 8v

v = -10m/s

Choice D

4 0
3 years ago
8. A 2 kg flower pot weighing 20 N falls from a window ledge.
Alina [70]

The force of the air resistance is 4 N.

The given parameters;

  • mass of the flower pot, m = 2 kg
  • weight of the flower pot, W = 20 N

Let the air resistance = F

Apply Newton's second law of motion to determine the force of the air resistance acting upward to oppose the motion of the pot falling downwards.

\Sigma F = ma\\\\W - F = ma\\\\a = \frac{W - F}{m} \\\\8 = \frac{20 - F}{2} \\\\20 - F = 16\\\\F = 20 - 16\\\\F = 4 \ N

Thus, the force of the air resistance is 4 N.

Learn more here: brainly.com/question/19887955

8 0
3 years ago
Refer to science 10 (mirror mirror on the wall)how do the height and width of the object compare with the height and width of th
Irina-Kira [14]

Depends on what type of mirror that is. I am going to assume this is a plain mirror (from the phrase), which means the height and width of the object and image is exactly the same.

6 0
3 years ago
If the speed of light in a substance is 2.26 x 10^8 m/s, what is the index of refraction of that substance?
vladimir1956 [14]

Answer:

1.33

Explanation:

speed of light in vacuum, c = 3 x 10^8 m/s

speed of light in medium, v = 2.26 x 10^8 m/s

The refractive index of the medium is given by

μ = speed of light in vacuum / speed of light in medium

μ = (3 x 10^8) / (2.26 x 10^8)

μ = 1.33

4 0
3 years ago
A rectangular loop of wire with width w = 5 cm, length L = 10cm, mass m = 40 g, and resistance R = 20 mΩ has an initial velocity
zhuklara [117]

Answer:

The loop penetrate 4 cm into the magnetic field.

Explanation:

Given that,

Width w= 5 cm

Length L= 10 cm

mass m = 40 g

Resistance R = 20 mΩ

Initial velocity = 1 m/s

Magnetic field = 2 T

We need to calculate the induced emf

Using formula of emf

\epsilon=v_{0}Bw

Put the value into the formula

\epsilon =1\times2\times5\times10^{-2}

\epsilon =10\times10^{-2}\ volt

We need to calculate the current

Using Lenz's formula

i=\dfrac{\epsilon}{R}

i=\dfrac{10\times10^{-2}}{20\times10^{-3}}

i=5\ A

We need to calculate the force

Using formula of force

F=i(\vec{w}\times\vec{B})

F=iwB

Put the value into the formula

F=5\times5\times10^{-2}\times2

F=0.5\ N

We need to calculate the acceleration

Using formula of acceleration

a=\dfrac{F}{m}

Put the value in to the formula

a=\dfrac{0.5}{40\times10^{-3}}

a=12.5\ m/s^2

We need to calculate the distance

Using equation of motion

v^2=u^2+2as

s=\dfrac{v^2-u^2}{2a}

s=\dfrac{0-1^2}{2\times(-12.5)}

s=0.04\ m

s=4\ cm

Hence, The loop penetrate 4 cm into the magnetic field.

5 0
3 years ago
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