A solid concrete block weighs 169 N and is resting on the ground. Its dimensions are
0.400m×0.200m×0.100m
A number of identical blocks are stacked on top of this one. What is the smallest number of whole blocks (including the one on the ground) that can be stacked so that their weight creates a pressure of at least two atmospheres on the ground beneath the first block?

Answer:

-63.6m/s

Explanation:

Given parameters:

Initial velocity  = 5m/s

Time of flight  = 7s

Unknown:

Velocity of the eraser after 7s = ?

Solution:

To solve this problem, we have to use the right motion equation which is given below;

          v  = u - gt

v is the final velocity

u is the initial velocity

g is the acceleration due to gravity  = 9.8m/s²

t is the time taken;

  Now insert the parameters and solve for v;

     v  = 5  - (9.8 x 7)  

    v   = -63.6m/s

Answer:

14.2

Explanation:

find horizontal force of the weight = 2.5kg x 9.8 Sin30 = 12.3 N

to prevent the sliding she needs to pull horizontally

Fh = 12.3 /Cos 30 =14.2N

The iron has, because it's displacing more water than the wood is.

Answer:

Hey

Explanation:

Answer:

The pH scale measures of how acidic or basic water is.

The pH scale also measures whether there is more hydronium or hydroxide in a solution.

Explanation:

The range goes from 0-14, with 7 being neutral. Less than 7 indicates acidity and more than seven indicates the substance is a base.

Answer:

a. E = 86.36 x 10⁻³ V/m = 86.36 mV/m

b. ρ = 3.6 x 10⁻⁷ Ωm

Explanation:

a.

The electric field in terms of the voltage is given by the following formula:

E = V/d

where,

E = Electric Field in the Wire = ?

V = Potential Difference = 3.8 V

d = distance between the points = 44 m

Therefore,

E = 3.8 V/44 m

E = 86.36 x 10⁻³ V/m = 86.36 mV/m

b.

Now, from Ohm's Law:

V = IR

R = V/I

where,

R = Resistance of wire = ?

I = Current = 3 A

Therefore,

R = 3.8 V/3 A

R = 1.27 Ω

Now, the resistance of a wire can be given as:

R = ρL/A

where,

ρ = resistivity of material = ?

L = Length = 44 m

A = Cross-sectional area = πr² = π(0.002 m)² =  1.25 x 10⁻⁵ m²

Therefore,

1.27 Ω = ρ*44 m/1.25 x 10⁻⁵ m²

(1.27 Ω)(1.25 x 10⁻⁵ m²)/44 m = ρ

ρ = 3.6 x 10⁻⁷ Ωm

Answer:

h = 51.75 m

nearest answer is:

53.4 m

Explanation:

First we analyze the horizontal motion. Since, the air friction is assumed to be negligible. Hence, the horizontal motion shall be uniform. Therefore,

s = V₀ₓ t

where,

s = horizontal distance = 39 m

V₀ₓ = Horizontal Initial Velocity = 12 m/s

t = time = ?

Therefore,

39 m = (12 m/s)t

t = 39 m/12 m/s

t = 3.25 s

Now, we analyze the vertical motion. Applying newton's second equation of motion to vertical motion:

h = V₀y t + (1/2)gt²

where,

h = height of cannon = ?

V₀y = initial vertical velocity = 0 m/s

g = 9.8 m/s²

Therefore,

h = (0 m/s)(3.25 s) + (1/2)(9.8 m/s²)(3.25 s)²

h = 51.75 m

Answer:

a. by moving the book without acceleration and keeping the height of the book constant

Explanation:

FOR CONSTANT KINETIC ENERGY:

The kinetic energy of a body depends upon its speed according to its formula:

ΔK.E = (1/2)mΔv²

So, for Δv = 0 m/s

ΔK.E = 0 J

So, for keeping kinetic energy constant, the books must be moved at constant speed without acceleration.

FOR CONSTANT POTENTIAL ENERGY:

The potential energy of a body depends upon its height according to its formula:

ΔP.E = mgΔh

So, for Δh = 0 m/s

ΔP.E = 0 J

So, for keeping potential energy constant, the books must be moved at constant height.

So, the correct option is:

a. by moving the book without acceleration and keeping the height of the book constant

Answer:

Answer:

1.45

Explanation:

Refractive index of the liquid is given as;

Refractive index = [tex]\frac{speed of light in vacuum}{speed of light in liquid}[/tex]

But,

speed = [tex]\frac{distance}{time}[/tex]

Since a certain light of specific wavelength was used during the same time, let the time be represented by t.

So that;

speed of light in vacuum = [tex]\frac{3500}{t}[/tex]

speed of light in the liquid = [tex]\frac{2350}{t}[/tex]

Refractive index = [tex]\frac{3500}{t}[/tex] ÷ [tex]\frac{2350}{t}[/tex]

                            = [tex]\frac{3500}{t}[/tex] x [tex]\frac{t}{2350}[/tex]

Refractive index = [tex]\frac{3500}{2350}[/tex]

                          = 1.4536

                          = 1.45

The refractive index of the liquid is 1.45.

Answer:

Work done, W = 2 J

Explanation:

Given that,

Weight of a book, W = F = 1 N

It is lifted to a height of 2 m

We need to find the work done. It can be calculated using the formula as follows :

W = F d

Put all the values,

W = 1 N × 2 m

W = 2 J

So, 2J of work was done.

Answer:

one of the graph is postion-time graph while the other one is velocity-time graph

Answer:

However, those astronauts would experience a second spectacle: A solar eclipse caused by the Earth – the Sun disappearing behind the dark disc of the Earth. When Earth inhabitants witness a lunar eclipse, Moon inhabitants would, simultaneously be witnessing a solar eclipse.

Answer:

V₀ₓ = 9.2 m/s

Nearest answer:

D) 8.9 m/s

Explanation:

First we find the time taken by the pumpkin to hit the car. For that purpose we apply 2nd equation of motion to the pumpkin:

h = V₀y t + (1/2)gt²

where,

h = height of building = 10.4 m

V₀y = vertical component of initial speed = 0 m/s

t = time = ?

g = 9.8 m/s²

Therefore,

10.4 m = (0 m/s)(t) + (1/2)(9.8 m/s²)t²

t² = (10.4 m)(2)/(9.8 m/s²)

t = √[2.122 s²]

t = 1.45 s

Now, we analyze horizontal motion for horizontal component of initial velocity. We assume air friction to be zero so that the horizontal motion is uniform. Therefore,

s = V₀ₓ t

where,

s = horizontal distance between building and car = 13.4 m

V₀ₓ = Horizontal Component of Initial Velocity = ?

Therefore,

13.4 m = V₀ₓ(1.45 s)

V₀ₓ = 13.4 m/1.45 s

V₀ₓ = 9.2 m/s

Answer:

Delivery truck

Explanation:

Answer:

Potential energy is the latent energy in an object at rest.

Explanation:

Hope this helps- this is how I would answer :)

Answer:

29223.6J

Explanation:

Given parameters:

Mass of Piano = 852kg

Height of lifting  = 3.5m

Unknown:

Gravitational potential energy  = ?

Solution:

The gravitational potential energy of a body can be expressed as the energy due to the position of a body;

  G.P.E  = mgh

m is the mass

g is the acceleration due to gravity

h is the height

 Now insert the given parameters and solve;

   G.P.E  = 852 x 9.8 x 3.5 = 29223.6J

The cars essentially finish where they started, their displacement is close to zero kilometers. However, the winning vehicles have traveled 500 miles.

The separation between two places of an item in motion is known as displacement. Therefore, it relies on both the starting position and the ending position. Displacement is also the shortest distance between the initial and ultimate places.

The distinction between two locations of an object is known as displacement. Because it has both a direction and magnitude, it qualifies as a vector quantity. The symbol for it is an arrow pointing from the first position to the final position. The cars essentially finish where they started, their displacement is close to zero kilometers. However, the winning vehicles have traveled 500 miles.

Therefore,  their displacement is close to zero kilometers.

To learn more about displacement, here:

https://brainly.com/question/10919017

#SPJ2

Explanation:

U = 40m/s

V = 30m/s

T = 5 sec

A = ?

[tex]a = \frac{u - v}{t}[/tex]

[tex]a = \frac{40 - 30}{5}[/tex]

[tex]a = \frac{10}{5}[/tex]

[tex]a = 2[/tex]

since it's decreasing in speed, The acceleration will be " - 2.0ms^-2 " or " - 2.0m/s^2 "

If you liked this answer, feel free to follow me for more!

Btw don't mind me answering twice. I want the free points and maybe another brainliest? lol.

Answer:

Explanation:

Velocity of train 130 km /hr

distance of crossing s = 500 m = .5 km

Time taken by train to reach crossing = .5 / 130 = .003846 hr = 13.85 s

Time taken by gangster to reach the crossing = t

initial velocity u = 100km/h = 27.77 m /s

distance of crossing s = 750 m

acceleration a = 4 m /s

s = ut + .5 a t²

750 = 27.77 t + .5 x 4 x t²

2 t² + 27.77 t - 750 = 0

t = - 27.77 ± √(27.77² + 4 x 2 x 750) / 2 x 2

= - 27.77 ±√ ( 771.17 + 6000) / 4

= - 27.77 ±82.28 / 4

= 13.62 s

So this time is less than time taken by train so it will be able to cross the crossing before train arrives .

We are given:

constant speed of the car (u) = 36.12 m/s

time in question (t) = 12 seconds

Solving for the Distance and Displacement:

from the second equation of motion:

s = ut + 1/2 at^2

since we have 0 acceleration:

s = ut

replacing the variables

s = 36.12 * 12

s = 433.44 m

Since the car is travelling in a straight line towards the same direction, it's Distance will be equal to its Displacement

Hence, both the Displacement and Distance covered by the car is

433.44 m

but since Displacement also has a direction vector along with it,

the Displacement will be  433.44 m due west

Answer:

[tex]14400\ \text{N}[/tex], Attractive

[tex]3240\ \text{N}[/tex], Repulsive

Explanation:

[tex]q_1[/tex] = -20 μC

[tex]q_2[/tex] = 50 μC

r = Distance between the charges = 2.5 cm

k = Coulomb constant = [tex]9\times 10^9\ \text{Nm}^2/\text{C}^2[/tex]

Electrical force is given by

[tex]F=\dfrac{kq_1q_2}{r^2}\\\Rightarrow F=\dfrac{9\times 10^9\times (-20\times 10^{-6})\times (50\times 10^{-6})}{(2.5\times10^{-2})^2}\\\Rightarrow F=-14400\ \text{N}[/tex]

The magnitude of force each sphere will experience is [tex]14400\ \text{N}[/tex]

Since the charges have opposite charges they will attract each other.

Now the charges are brought into contact with each other so the resultant charge will be

[tex]q=\dfrac{q_1+q_2}{2}\\\Rightarrow q=\dfrac{-20+50}{2}\\\Rightarrow q=15\ \mu\text{C}[/tex]

[tex]F=\dfrac{kq^2}{r^2}\\\Rightarrow F=\dfrac{9\times 10^9\times (15\times 10^{-6})^2}{(2.5\times 10^{-2})^2}\\\Rightarrow F=3240\ \text{N}[/tex]

The magntude of the force the spheres experience will be [tex]3240\ \text{N}[/tex]

The spheres have the same charge now so they will repel each other.

Answer:

45.9m

Explanation:

Given parameters:

Final velocity  = 30m/s

Initial velocity  = 0m/s

Unknown:

Time it takes for the object of fall  = ?

Height of fall = ?

Solution:

For the first problem, we use the equation below to solve for t;

      V = U + gt

V is the final velocity

U is the initial velocity

g is the acceleration due to gravity

t is the time taken

          30  = 0 + 9.8 x t

          30  = 9.8t

            t  = [tex]\frac{30}{9.8}[/tex]  = 3.1s

Now, height of fall;

  V² = U²  + 2gH

   30² = 0² + 2 x 9.8 x H

   900  = 19.6H

      H  = 45.9m

Explanation:

yooooooooo

Answer:

Silver

Explanation:

Silver is an important element in the manufacturing process of mirrors. Silver is used to make mirrors through the process we call "silvering". Silvering is a process in which a glass is coated with reflective substances so as to produce reflections, and then mirrors.

In Silvering process, Chlorine is also used. Stannous Chloride is the particular compound used to carry out the silvering, it has the chemical formula, SnCl₂

Answer:

Umm sorry just came for the points.

Answer:

The stress is  [tex]\sigma = 1.218*10^{6} \ N/m^2[/tex]

Explanation:

From the question we are told that

   The diameter of the post is  [tex]d = 29 \ cm = 0.29 \ m[/tex]

   The length is [tex]L = 2.0 \ m[/tex]

    The weight of the loading mass

Generally  the  radius of the post is mathematically represented as

     [tex]r = \frac{0.29}{2}[/tex]

=>   [tex]r = 0.145 \ m[/tex]

Generally the area of the post is  

       [tex]A = \pi r^2[/tex]

=>     [tex]A = 3.14 * 0.145 ^2[/tex]

=>     [tex]A = 0.066 \ m^2[/tex]

Generally the weight exerted by the load is mathematically represented as

        [tex]F = m * g[/tex]

=>      [tex]F = 8200 * 9.8[/tex]

=>      [tex]F = 80360 \ N[/tex]

Generally the stress is mathematically represented as

         [tex]\sigma = \frac{F}{A}[/tex]

=>      [tex]\sigma = \frac{80360 }{0.066}[/tex]

=>      [tex]\sigma = 1.218*10^{6} \ N/m^2[/tex]

Answer:

7.62

Explanation:

because you have to divide 32/4.2

and can you do a friend request so i can accept it