28. A car is traveling east at an unknown initial velocity. Without changing directions, it accelerates at 0.75 m/s²
for a distance of 300 m, increasing its velocity to 30 m/s. What was the initial velocity of the car?

Answer:

500 Hz

Explanation:

Formula for finding wave frequency is,

f = c/λ

f = frequency

c = speed (m/s)

λ = wave length (m)

f = c/λ

f = 280/0.56

f = 500

∴ wave frequency is 500 Hz

Answer:

The atomic mass of an element is affected by the distribution of its isotopes because each isotope of an element has a different number of neutrons in the nuclei of its atoms.

Explanation:

please give me brainlyiest if its right

Answer:

convection it's your answer plz make me brainy least

Answer:

The mass formula is also given as m = F / a If acceleration itself is the gravity, then M = F / g

please mark me as brainleist

Answer:Unlike fixed joints or cartilaginous joints, where the bones are connected by either connective tissue or cartilage, the bones in synovial joints are not directly joined by anything, which allows for a much greater range of motion.

Explanation: I got a 100% on my test

Answer:

[tex]4.61\times 10^{-5}\ \text{T}[/tex]

[tex]1.05\times 10^{-6}\ \text{Nm}[/tex]

Explanation:

[tex]\mu_0[/tex] = Vacuum permeability = [tex]4\pi10^{-7}\ \text{H/m}[/tex]

[tex]r_l[/tex] = Radius of loop = 15 cm

[tex]I_l[/tex] = Current in loop = 11 A

[tex]r_c[/tex] = Radius of coil = 0.76 cm

N = Number of turns of coil = 66

[tex]I_c[/tex] = Current in coil = 1.9 A

Magnetic field is given by

[tex]B=\dfrac{\mu_0I_l}{2r_l}\\\Rightarrow B=\dfrac{4\pi\times 10^{-7}\times 11}{2\times 0.15}\\\Rightarrow B=4.61\times 10^{-5}\ \text{T}[/tex]

Magnitude of magnetic field produced by the loop at its center is [tex]4.61\times 10^{-5}\ \text{T}[/tex].

Torque is given by

[tex]\tau=BI_c\pi r_c^2N\sin90^{\circ}\\\Rightarrow \tau=4.61\times 10^{-5}\times 1.9\times \pi\times (0.76\times 10^{-2})^2\times 66\sin90^{\circ}\\\Rightarrow \tau=1.05\times 10^{-6}\ \text{Nm}[/tex]

Magnitude of torque on the coil due to the loop is [tex]1.05\times 10^{-6}\ \text{Nm}[/tex]

Answer:

B.

Explanation:

Answer: A or B

Explanation: I’m guessing that they even each other out depending on the incline, gravity will help keeping it in place

Answer: [tex]1.875\ rad/s^2, 8\ s[/tex]

Explanation:

Given

Radius of disc [tex]r=10\ cm[/tex]

Angle turned [tex]\theta=60\ rad[/tex]

Initial angular velocity [tex]\omega_0=0[/tex]

Final angular velocity [tex]\omega_f=15\ rad/s[/tex]

using [tex]\omega^2-\omega_o^2=2\alpha \cdot \theta[/tex]

Substitute values

[tex]\Rightarrow 15^2-0=2\times \alpha \times 60\\\Rightarrow \alpha=1.875\ rad/s^2[/tex]

using [tex]\omega=\omega_o+\alpha t[/tex]

Substitute values

[tex]\Rightarrow 15=0+1.875\times t\\\Rightarrow t=8\ s[/tex]

Answer:

8,6 is the answer to your question

Explanation:

Given that,

⠀⠀⠀⇒ S′ = u + a/2(2n ― 1)

⠀⠀⠀⇒8 = u + a/2× [2(1) ― 1]

⠀⠀⠀⇒8 = u + a/2× [2 ― 1]

⠀⠀⠀⇒8 = u + a/2× 1

⠀⠀⠀⇒8 = u + a/2⠀⠀⠀⠀⠀ … ( 1 )

And,

⠀⠀⠀⇒ S″ = u + a/2(2n ― 1)

⠀⠀⠀⇒12 = u + a/2× [2(2) ― 1]

⠀⠀⠀⇒12 = u + a/2× [4 ― 1]

⠀⠀⠀⇒12 = u + a/2× 3

⠀⠀⠀⇒12 = u + 3a/2⠀⠀⠀⠀ … ( 2 )

Subtract ( 1 ) from ( 2 ).

⠀⠀⠀⇒12 ― 8 = u + 3a/2 ― (u + a/2)

⠀⠀⠀⇒4 = u + 3a/2 ― u ― a/2

⠀⠀⠀⇒4 = 3a/2 ― a/2

⠀⠀⠀⇒4 = 2a/2

⠀⠀⠀⇒4 × 2 = 2a

⠀⠀⠀⇒8 = 2a

⠀⠀⠀⇒8 ÷ 2 = a

⠀⠀⠀⇒4 m/s² = a⠀⠀⠀⠀⠀[Ans]

Substitute the value of a in equation ( 1 ).

⠀⠀⠀⇒8 = u + a/2⠀⠀⠀⠀⠀ … ( 1 )

⠀⠀⠀⇒8 = u + 4/2

⠀⠀⠀⇒8 = u + 2

⠀⠀⠀⇒8 ― 2 = u

⠀⠀⠀⇒6 m/s = u⠀⠀⠀⠀⠀[Ans]

Now, distance travelled in third second.

⠀⠀⠀⇒ S′″ = u + a/2(2n ― 1)

⠀⠀⠀⇒ S′″ = 6 + 4/2 × [2(3) ― 1]

⠀⠀⠀⇒ S′″ = 6 + 2 × [6 ― 1]

⠀⠀⠀⇒ S′″ = 6 + 2(5)

⠀⠀⠀⇒ S′″ = 6 + 10

⠀⠀⠀⇒ S′″ = 16 m⠀⠀⠀⠀⠀[Ans]

Answer:

Wax melts as it absorb heat from flame

Explanation:

To know which option is correct, it is important that we know what chemical changes and physical changes are all about.

Chemical change is a change in which the process is not easily reversed and it produces new substance.

Physical change is more like the opposite of chemical change. In this change, the process is easily reversed and no new substance is produced.

Considering the options given above,

1. Iron combines with oxygen to produce rust is a chemical change since a new substance (rust) is formed and we can not reverse the process to get back iron and oxygen.

2. Wax melts as it absorb heat from flame is a physical change since no new substance is formed and we obtained the wax by allowing it to solidified.

3. Pure sodium explodes when dropped in water is a chemical change because we can not reverse the process to get back the sodium.

4. Glucose molecules are produced in plant leaf is also a chemical change.

From the illustrations above, it is evident that: 'Wax melts as it absorb heat from flame' is not a chemical

Answer:

Drink water at least every 5 to 20 minutes while exercising in hot weather.

Explanation:

Hope this helps brainliest please

Answer:

K.E = 6.4 × 10⁻¹⁶

Velocity = 4.39 × 10⁴ m/sec

Explanation:

From the given information:

The average K.E = P.E (potential energy)

Thus, K.E = q × V

K.E = 1.6 × 10⁻¹⁹ × 4000 V

K.E = 6.4 × 10⁻¹⁶

However,

[tex]K.E = \dfrac{1}{2}mv^2[/tex]

[tex]6.4 \times 10^{-16} = \dfrac{1}{2}(400 \times 1.66 \times 10^{-27} ) \times v^2[/tex]

[tex]\dfrac{6.4 \times 10^{-16} }{\dfrac{1}{2}(400 \times 1.66 \times 10^{-27} )}= v^2[/tex]

[tex]v^2=1.92771084 \times 10^9\\ \\ v=\sqrt{ 1.92771084 \times 10^9} \\ \\ v = 43905.7 \\ \\ \mathbf{v = 4.39 \times 10^4 \ m/sec}[/tex]

Answer:

    w = - 197.5 rad / s

The negative sign indicates that the rotations are clockwise

Explanation:

To solve this exercise, let's use the concept of conservation of the angular number.

We create a system formed by the two discs, in this case the forces last the shock are internal

initial instant .. just before shock

           L₀ = I₀ w₀ + I₁ w₁

instnte final. Right after crash

           L_f = (I₀ + I1) w

angular momentum is conserved

           I₀ w₀ + I₁ w₁ = (I₀ + I₁) w

           w = I₀ w₀ + I₁ w₁ / Io + I1

The moment of inertia of a disk with an axis passing through its thermometric center

          I₀ = ½ m² r₀²

          I₁ = ½ m₁ r₁²

         we substitute

          I₀ = ½ 2.0 0.70²

          I₀ = 0.49 kg m

          I₁ = ½ 2.0 0.5²

          I₁ = 0.25

₁  

let's reduce the magnitudes the SI system

          w₀ = -50 rev / (2pi rad / 1rev) = -314.15 rad / s

          w₁ = 70 rev (2pi rad / 1rev) = 439.82 rad / s

we will assume that the counterclockwise turns are positive

           w = -0.49 314.15 + 0.25 439.82 / (0.49 + 0.25)

            w = (- 4.696 + 1.0995) 102) / 0.74

            w = -197.75 + 0.25

            w = - 197.5 rad / s

The negative sign indicates that the rotations are clockwise

Answer:

332m/s

Explanation:

We know the formula for velocity is v=d/t, but this particular question is asking about an echo. The problem tells us the distance to the bird from the bat, which is 19.4. To find the echo, you need to find the distance from the bat to the bird and back.

So

19.4 x 2 = 38.8

And then plug into the equation

v = 38.8 / 0.117

= 332m/s

Answer:

What are your options? also i believe the answer may be ecosystem.

Explanation:

There are both biotic and abiotic factors in an ecosystem. Be cause living organisms Are Biotic. While water and rocks are abiotic which are needed to form an ecosystem.

Answer:

I think it would most likely be 2... but not so sureee

Answer:

5 watts

power = work done ÷ time taken

10 j ÷ 2 = 5w

let the volume be x

19 = 38/x

x=38/19

x=2

volume is 2 cm^3

Answer:

8.162

Explanation:

W=mg

  = 2.2 x 3.71

  = 8.162 N

Answer:

Momentum - Momentum is a measurement of mass in motion. Momentum is equal to the mass times the velocity of an object.

Answer:

The building was Painted

The building was painted last year by someone.

Answer:

All of the above.

Explanation:

A person is said to be at rest when he or she is not performing any action. The heartbeat stays normal in this condition.

A person is said to perform a moderate activity when his heart beats faster than the normal rest condition. It requires extra effort within the limit. For example, walking and dancing are examples of moderate activity.

A person is said to perform a vigorous activity when his heart beats much than in moderate activity. It requires a lot of effort over the limit. Running is an example of vigorous activity.

In view of the above information, all the options given in the question are true. Hence, the correct answer will be:

All of the above.

Answer:

C. The change of internal energy of a system is the sum of work and heat spent on it.

Explanation:

The law of conservation of Energy states that energy cannot be destroyed but can only be converted or transformed from one form to another. Therefore, the sum of the initial kinetic energy and potential energy is equal to the sum of the final kinetic energy and potential energy.

Mathematically, it is given by the formula;

Ki + Ui = Kf + Uf .......equation 1

Where;

Ki and Kf are the initial and final kinetic energy respectively.

Ui and Uf are the initial and final potential energy respectively.

The law of conservation of Energy is another way to describe the law of Thermodynamics. It states that the change of internal energy of a system is the sum of work and heat spent on it.

Mathematically, it is given by the formula;

ΔU = Q − W

Where;

ΔU represents the change in internal energy of a system.

Q represents the net heat transfer in and out of the system.

W represents the sum of work (net work) done on or by the system.