A square is cut out of a copper sheet. Two straight scratches on the surface of the square intersect forming an angle theta. The square is heated uniformly. As a result, the angle between the scratches?a) increasesb) decreasesc) stays the samed) depends on whether theta is obtuse or acute

Answer:

True

Explanation:

Thats is true since it cannot be a vector because speed only gives a magnitude, not a direction as well.

Answer:

The correct option is;

a. 12.5 g

Explanation:

The given parameters are;

The initial mass of the radioactive substance = 200 g

The half life of the radioactive substance = 50 years

The time duration for the disintegration = 200 years

The formula for half life is given as follows;

[tex]N(t) = N_0 \left (\dfrac{1}{2} \right )^{\dfrac{t}{t_{1/2}}[/tex]

Where:

N(t) = Quantity of the remaining substance

N₀ = Initial radioactive substance quantity  = 200 g

t = Time duration  = 200 years

[tex]t_{1/2}[/tex] = Half life of the radioactive substance  50 years

Therefore, we have;

[tex]N(t) =200 \times \left (\dfrac{1}{2} \right )^{\dfrac{200}{50} } =200 \times \left (\dfrac{1}{2} \right )^4 = 12.5 \ g[/tex]

Therefore, at the end of 200 years, the quantity left = 12.5 g.

Answer:

Ra, 88

Ru, 44

Cr, 24

Explanation:

i

the remaining mass number is 224(228 - 4), and it's atomic number is 88(90 - 2). The element is Radium, Ra

ii

the remaining mass number is 98(98 - 0), and it's atomic number is 44(45 - 1). The element is Ruthenium, Ru

iii

The remaining mass number is 52(52 - 0), and it's atomic number is 24(23 - -1). The element is Chromium, Cr

Answer:

F = 0.408 N

Explanation:

It is given that,

Weight of a wooden block, W = 8 N

Weight, W = mg

m is mass of wooden block

[tex]m=\dfrac{W}{g}\\\\m=\dfrac{8\ N}{9.8\ m/s^2}\\\\m=0.816\ kg[/tex]

Acceleration of the block, a = 0.5 m/s²

Force, F = ma

[tex]F=0.816\ kg\times 0.5\ m/s^2\\\\F=0.408\ N[/tex]

So, the magnitude of force applied to the wooden block is 0.408 N.

Explanation:

Hi,

The answer is friction.

There is almost no machine which are not affected by friction. It losts some work due to friction while working.

Hope it helps..

Answer:

friction

Explanation:

the other options dont effect efficiency

Answer:

The time she takes to reach the water from when she jumps off the platform is 1.71 s

Explanation:

According to the equations of motion, we have;

v = u - g·t

v² = u² - 2·g·s

s₁ = u₁·t₁ + 1/2·g₁·t₁²

The given parameters are;

The height of the platform (assumption: above the water) = 10 m

The velocity with which she jumps, u = 3 m/s

The acceleration due to gravity, g = 9.81 m/s²

The height to which she jumps, s, is found as follows;

v² = u² - 2·g·s

At maximum height, v = 0, which gives;

0 = 3² - 2×9.81×s

2×9.81×s = 3² = 9

s = 9/(2×9.81) = 0.4587 m

s = 0.4587 m

The time to maximum height, t, is found as follows;

v = u - g·t

0 = 3 - 9.81×t

9.81×t = 3

t = 3/9.81 = 0.3058 s

The total distance, s₁ from maximum height to the water surface = s + 10 = 0.4587 + 10 = 10.4587 m = 10.46 m

The time to reach the water from maximum height, t₁, is found as follows;

s₁ = u₁·t₁ + 1/2·g₁·t₁²

Where;

s₁ =  The total distance from maximum height to the water surface = 10.46 m

u₁ = The initial velocity, this time from the maximum height = 0 m/s

g₁ = The acceleration due to gravity, g (positive this time as the diver is accelerating down) = 9.81 m/s²

t₁ = The time to reach the water from maximum height

Substituting the values gives;

s₁ = u₁·t₁ + 1/2·g₁·t₁²

10.46 = 0·t₁ + 1/2·9.81·t₁²

t₁²= 10.46/(1/2×9.81) = 2.13 s²

t₁ = √2.13  = 1.46 s

Total time = t₁ + t = 1.46 + 0.3058 = 1.7066 ≈ 1.71 s.

Therefore, the time she takes to reach the water from when she jumps off the platform = 1.71 s.

Answer:

The tension in the rod as the ball moves through the bottom circle is 9.8 N

Explanation:

When the ball is released from rest, the centripetal force equals the weight of the ball. So mv²/r = mg where m = mass of ball = 0.5 kg, v = speed of ball, r = radius of vertical circle = length of rod = 0.5 m and g = acceleration due to gravity = 9.8 m/s²

v = √gr = √9.8 m/s² × 0.5 m = √4.9 = 2.21 m/s

Now at the bottom of the circle T - mg = mv²/r where T = tension in the rod

T = m(g + v²/r)

= m(g + (√gr)²/r)

= m(g+ gr/r)

= m(g + g)

= 2mg

= 2 × 0.5 kg × 9.8 m/s²

= 9.8 N

So, the tension in the rod as the ball moves through the bottom circle is 9.8 N

Answer:

D

Explanation:

The answer is D because:

A) Only doctors are allowed to prescribe medications.

B) Rita is not a chef/cook.

C) Rita is not a personal trainer

D) The job of a dietican is to provide reccomendations to their clients in order for them to implement a healthy lifestyle via consuming what is best for them.

Hope this helps :)

Answer:

D.) Making recommendations for healthy eating habits

Explanation: PLATO :)))

Answer:

usa

Explanation:

Answer:

a=F/m

a=12N/3kg  (here newton can be written as kgm/s^2 so kg will be cancelled)

a=4m/s^2

Explanation:

Answer:

The spring was compressed the following amount:

[tex]\Delta x=\sqrt{ \frac{m_1\,v_1^2+ m_2\,v_2^2}{k} }[/tex]

Explanation:

Use conservation of energy between initial and final state, considering that the surface id frictionless, and there is no loss in thermal energy due to friction. the total initial energy is the potential energy of the compressed spring (by an amount [tex]\Delta x[/tex]), and the total final energy is the addition of the kinetic energies of both masses:

[tex]E_i=\frac{1}{2} k\,(\Delta x)^2\\\\E_f=\frac{1}{2} m_1\,v_1^2+\frac{1}{2} m_2\,v_2^2[/tex]

[tex]E_i=E_f\\[/tex]

[tex]\frac{1}{2} k\,(\Delta x)^2=\frac{1}{2} m_1\,v_1^2+\frac{1}{2} m_2\,v_2^2\\k\,(\Delta x)^2=m_1\,v_1^2+ m_2\,v_2^2\\(\Delta x)^2=\frac{m_1\,v_1^2+ m_2\,v_2^2}{k} \\\Delta x=\sqrt{ \frac{m_1\,v_1^2+ m_2\,v_2^2}{k} }[/tex]

Answer:

D

Explanation:

because light has no space nor mass

Answer:

SI units are the physical units of measurement. SI units include kilogram, meter, second, ampere, kelvin, candela, and mole etcetera.

SI units are very important for daily life while measuring daily life commodities, such as:

Without SI units, it would be difficult to meausre the amount of object required or any other measurement object.

Answer: ear phones

Explanation:

You can physically hold ear phones, but you can't hold music, sunlight, or heat.

Answer:

6.0×10⁻²¹ J

Explanation:

KE = 3/2 kT,

where KE is average kinetic energy per molecule,

k is the Boltzmann constant,

and T is absolute temperature.

KE = 3/2 (1.38×10⁻²³ J/K) (18 + 273.15) K

KE = 6.0×10⁻²¹ J

Answer:

The answer is 6.0×10⁻²¹ J , because KE = 3/2 kT,  where KE is average kinetic energy per molecule,  k is the Boltzmann constant,  and T is the absolute temperature.

KE = 3/2 (1.38×10⁻²³ J/K) (18 + 273.15) K

KE = 6.0×10⁻²¹ J

Answer:

C. Walk four times per week

Explanation:

If she wants to increase her time then, she has to walk four times per week.

The total distance covered by any object per unit of time is known as speed. It depends only on the magnitude of the moving object. The unit of speed is a meter/second. The generally considered unit for speed is a meter per second.

The mathematical expression for speed is given by

speed = total distance /Total time

As given in the problem Lyla walks three times per week for 45 minutes at a speed of 4.0 miles per hour. She must walk four times a week if she wants to extend her time.

Thus, the correct answer is option C.

Learn more about speed from here, refer to the link;

brainly.com/question/7359669

#SPJ2

The question is incomplete, the complete question is,

Lyla walks three times per week for 45 minutes at a speed of 4.0 miles per hour. She wants to increase her time. What should she do?

A. Walk at 4.5 miles per hour.

B. Walk for 50 minutes.

C. Walk four times per week.

D. Walk up and down more hills.

Answer:

Solution

Given:

initial velocity (u)=0m/s (because an object

starts from the rest)

time (t)=3sec

diatance travelled(s)=14m(16-2=14)

acceleration (a)=?

Now,

According to the formula

s=ut+1/2at^2

or,14 =0×3+1/2×a×3^2

or, 14=0+a/2×9

or, 14=9a/2

or, 9a=28

or, a=28/9

or, a=3.1 m/s^2

Therefore, the acceleration of the object is 3.1m/s^2 ans.

Answer;

7.238°

Explanation

From question we know that the grating has 1,970 grooves per centimeter, we can convert to from (cm) to (nm) for unit consistency

The slit separation is expressed below

d=1cm/1970

d=0.0005076

=5076nm

Then the angle (in degrees) that the red light of wavelength 640 nm appear in first order can be calculated using expression below

Sin(x)= mλ/d

Where λ= wavelength=640 nm

d=slit separation

Sin(x)= mλ/d

Sin(x)=(1×640)/5076

=0.126

sin-1(0.126)

X= 7.238°

Therefore,the angle (in degrees) that the red light of wavelength 640 nm appear in first order is 7.238°

Answer:

1.05×10⁻⁴ m²

Explanation:

ΔA = 2 A₀ α ΔT,

where ΔA is the change in area,

A₀ is the initial area,

α is the linear expansion coefficient,

and ΔT is the change in temperature.

A₀ = π (0.20 m / 2)² = 0.0314 m².

For steel, α = 13×10⁻⁶ /°C.

ΔT = 150°C − 22°C = 128°C.

ΔA = 2 (0.0314 m²) (13×10⁻⁶ /°C) (128°C)

ΔA = 1.05×10⁻⁴ m²

Answer:

When we have irregular objects, it may become very hard to calculate the volume of the object, as we actually can not use any simple equation to find it.

The mass is less tricky, just find a scale and wheight it, now we know the mass of the irregular object.

One way to measure the volume of the object is using water... how we do it?

Get some recipient with water, measure the height of the water.

Introduce your object into the water and totally submerge it, now the level of the water will rise. This is because as you introduce the object under the water, you are displacing up a given volume of water that has the same volume as the irregular object.

Now that you know the height of the water before and after you put your object, you can easily calculate the volume of water displaced, and that will be the volume of the object (the tricky part may be totally submerging the object if, for example, is wood and it floats, here you can use a thin wire to push it down but it will affect a little bit the measures.)

Answer:

230 = x + 105

x= 125

Explanation:

v = v0 + at

Answer:

$876.96

Explanation:

The energy used is:

3500 W × (24 hr/day) × (120 day) × (1 kW / 1000 W) = 10,080 kWh.

So the cost is:

10,080 kWh × ($0.087 / kWh) = $876.96

Explanation:

a) Acceleration is the slope of the velocity vs time graph.  When velocity vs time is a straight line, that means the acceleration is a constant.  F = ma, so the resultant force is also constant.

b) As air resistance increases, the acceleration begins to decrease.

c) A falling object stops accelerating when it reaches terminal velocity.

d) F = ma, so when the acceleration is 0, the resultant force is also 0.

Answer:

Parachutes

Explanation:

Your parachute allows you to descend more slowly because it lowers terminal velocity by increasing your air resistance. Most parachutes are designed to create a large amount of drag and allow you to land at a safe, low speed.

HOPE THIS HELPS!!!

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Answer:

The distance Mr Franklin applied the force is 400 m

Explanation:

The efficiency of the machine = 80%

The force applied by the machine = 800 N

The distance over which the force is applied by the machine = 20 m

The force applied by Mr. Franklin = 50 N

The work done by the machine = 800 × 20 = 16000 J

The ideal work at 100% efficiency = X

80% of X = 16000 J

X = 16000 N/0.8 = 20,000 J

Therefore, we have have;

Work = Force × Distance;

20,000 J = 50 N × Distance Mr Franklin applied the force

Distance Mr Franklin applied the force = 20,000 J/(50 N) = 400 m

The distance Mr Franklin applied the force = 400 m.

Answer:

the awnser in 400m

Explanation:

did the test on edge 2020 and got it right

It isn't best to wear loose fitting clothing when exercising, as you may not feel too comfortable. It depends on the person. However there are a few advantages.

• Tight clothing may not be comfortable as well

• Looser clothing allows easy evaporation of sweat

Then again when it says " loose - fitting " it may mean not too baggy. Baggy clothing can have an impact on your physical activity.

Answer All of the above

For people on a p e x

Answer:

Explanation:

Heat is transferred in the following ways listed below

1. Conduction(Through direct contact of particles )

2. Convection(Through motion of hot and cold liquid )

3. Radiation(Through electromagnetic waves Through the rising of a warm gas )

1. Conduction: This has to do with the transfer of heat from one medium to another having direct contact with each other, the medium can either be solid or liquids

2. Convection: Has to do with the transfer of heat energy via molecules of the liquids in motion with different or varying temperature gradients

3. Radiation: Mostly occurs in gases, it is the transfer of energy through waves

Answer:

236.8 cm

Explanation:

1 yr = 365 days = (365×24×60×60) secs

= 32 × 10^6

distace = velocity × time

= 7.4 × 10^-6 × 32 × 10^6

= 236.8 cm

The glacier will move 976.8 cm when it advances at 7.4 7.4×10⁻⁶ cm/s in 4.2 y

From the question above when we talk about how far, is still the same as distance.

Applying the equation of velocity,

V = d/t................... Equation 1

Where V = velocity, d = distance, t = time

make d the subject of equation 1

d = Vt................ Equation 2

From the question,

Given: V = 7.4×10⁻⁶ cm/s, t = 4.2 year = (4.2×3.154×10⁷) seconds = 1.32×10⁸ seconds

Substitute these values into equation 2

d = (7.4×10⁻⁶)(1.32×10⁸)

d = 9.768×10² cm

d = 976.8 cm

Hence the glacier will advances 976.8 cm

Learn more about distance here: https://brainly.com/question/22491931

Answer:

Fnet = F√2

Fnet = kq²/r² √2

Explanation:

A exerts a force F on B, and C exerts an equal force F on B perpendicular to that.  The net force can be found with Pythagorean theorem:

Fnet = √(F² + F²)

Fnet = F√2

The force between two charges particles is:

F = k q₁ q₂ / r²

where

k is Coulomb's constant, q₁ and q₂ are the charges, and r is the distance between the charges.

If we say the charge of each particle is q, then:

F = kq²/r²

Substituting:

Fnet = kq²/r² √2

Answer:

The atom is mostly empty space.

Explanation:

Ernest Rutherford in the year 1911 developed a model of an atom. In his model the atom was shown that the atom is mostly empty spaces composed of negative electrons which orbits round a positive nucleus just like planets revolving round the sun.

Rutherford came up with this model by performing experiments in 1909 which involves the scattering of alpha particles on a thin gold foil. From this experiments he came up with his model.

Answer:

A!

Explanation:

The atom is mostly empty space.