PHYSICS
HIGH SCHOOL

B. The same thing as heat energy

C. A direct measure of internal kinetic energy

D. The amount of calories in a substance

E. A direct measure of external kinetic energy

Answer:

Answer:

C. A direct measure of internal kinetic energy

Explanation: Temperature is defined by kinetic theory as the measure of the average kinetic energy of the particles that make up a substance.

Answer: A. An indirect measure of heat energy

HIGH SCHOOL

As a compass finds the northern direction,which of the following is it aligning with ? A.electrical field of earth

B.magnetic resistance of earth

C.magnetic metal of earth

D.magnetic field of earth

Answer:

D.magnetic field of earth

Explanation:

Magnetic compass is having a magnetic needle in it.

This magnetic needle will deflect in the direction of the magnetic field where it is placed

So when we place the magnetic needle or compass at any place on the Earth surface it always shows the Northern direction.

It is because our Earth has its own magnetic field which will apply torque on the magnetic needle due to which the needle will align itself into the direction of field.

So here the correct answer will be

D.magnetic field of earth

D.magnetic field of earth

HIGH SCHOOL

An airplane is flying with constant speed of 300 m/s along a horizontal circle with a radius of 15,000 m. if the lift force of the air on the wings is perpendicular to the wings, at what angle relative to the horizontal should the wings be banked?

Angle; θ ≈ 31. 5°

This question involves centripetal motion and angle of elevation.

- We are told that the lift force of the air on the wings is perpendicular to the wings.

This means, from centripetal motion we can write the force as;

F•sin θ = mv²/r - - - (1)

Where θ is the angle relative to the horizontal if the wings are banked.

r is radius

v is speed

- Similarly, resolving the force Component along the horizontal x-axis, we will have;

F•cos θ = mg - - - (eq 2)

- We are given radius and speed but we don't have force (F) and mass(M). Thus, we can eliminate them by dividing equation 1 by equation 2 to get;

(F•sin θ)/(F•cos θ) = (mv²/r)/mg

tan θ = v²/rg

Plugging in the relevant values L, we have;

tan θ = 300²/(15000 × 9.8)

tan θ = 0.6122

θ = tan^(-1) 0.6122

θ ≈ 31. 5°

Read more at; brainly.com/question/13692301

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MIDDLE SCHOOL

Why do copper vessels turn green with the passage of time?

oxidation due to where air hits it

Answer:

Copper turns green because of chemical reactions with the elements. Just as iron that is left unprotected in open air will corrode and form a flaky orange-red outer layer, copper that is exposed to the elements undergoes a series of chemical reactions that give the shiny metal a pale green outer layer called a patina

COLLEGE

When operated on a household 110.0-V line, typical hair dryers draw about 1650 W of power. We can model the current as a long straight wire in the handlé. During use, the current is about 1.85 cm from the user's hand. What is the current in the dryer? Number What is the resistance of the dryer? Number What magnetic field does the dryer produce at the user's hand?

The current in the dryer is 15 A.

The resistance of the dryer is 7.33 ohms

The magnetic field the dryer produced at the user's hand is 1.62 x 10⁻⁴ T.

Current in the dryerThe current in the dryer is calculated as follows;

I = P/V

I = 1650/110

I = 15 A

Resistance of the dryerThe resistance of the dryer is calculated as follows;

R = V/I

R = 11O/15

R = 7.33 ohms

Magnetic field produced by the dryerLearn more about magnetic field strength here: brainly.com/question/26257705

Answer:

Current = 15 A

Resistance = 7.33 ohm

Magnetic field = 1.62 x 10^-4 Tesla

Explanation:

V = 110 V, P = 1650 W, r = 1.85 cm,

(a) Let i be the current

P = V x i

i = 1650 / 110 = 15 A

(b) Let R be the resistance

V = i R

R = 110 / 15 = 7.33 Ohm

(c) Let B be the magnetic field

B = μ0 / 4π x 2i / r

B = 10^-7 x 2 x 15 / 0.0185 = 1.62 x 10^-4 Tesla

HIGH SCHOOL

A boy kicks a football with an initial velocity of 28.0 m/s at an angle of 30.0o above the horizontal. what is the highest elevation reached by the football in its trajectory?

As the boy kicks the football with an angle, due to the effect of the gravitational force, the ball would follow a projectile path which is parabolic in nature. From this idea, we can derive equations pertaining to the maximum height that the ball would reach. At the maximum height of the ball, the velocity of the ball would be equal to zero. From the equations for projectile motion, we would obtain the equation as follows:

Maximum height = v0^2 sin^2 (theta) / 2g

Maximum height = (28.0 m / s )^2 sin^2 (30.0) / 2(9.8 m / s^2)

Maximum height = 10 m

The maximum height that the ball would reach would be 10 m.

Maximum height = v0^2 sin^2 (theta) / 2g

Maximum height = (28.0 m / s )^2 sin^2 (30.0) / 2(9.8 m / s^2)

Maximum height = 10 m

The maximum height that the ball would reach would be 10 m.

COLLEGE

A 0.20 kg object, attached to a spring with spring constant k = 10 N/m, is moving on a horizontal frictionless surface in simple harmonic motion of amplitude of 0.080 m. What is its speed at the instant when its displacement is 0.040 m? (Hint: Use conservation of energy.)

Answer:

v = 0.566 m / s

Explanation:

Let's use energy conservation at two points the most extreme point of maximum elongation and the point of interest

Initial maximum elongation

Em₀ = = ½ k x²

At this point x = A = 0.080 m

Final point of interest

= K = ½ m v²

Energy is conserved

Em₀ =

½ k A² = ½ m v²

v² = k / m A²

v = √(k/m) A

Let's calculate

v = √ (10 / 0.20) 0.080

v = 0.566 m / s

COLLEGE

Consider water flowing through a cylindrical pipe with a variable cross-section. The velocity is v at a point where the pipe diameter is 1.0 cm. At a point where the pipe diameter is three times larger, the velocity is: nine times larger than the initial velocity

one ninth the initial velocity

three times larger than the initial velocity

the same as the initial velocity

one third the initial velocity

Answer:

one ninth

Explanation:

d = 1 cm , v = v

D = 3d, V = ?

By the equation of continuity,

A V = a v

3.14 x D^2 / 4 x V = 3.14 x d^2 / 4 x v

9d^2 x V = d^2 x v

V = v / 9

Thus, the velocity becomes one ninth the initial velocity

HIGH SCHOOL

Tarzan swings from a vine. at the bottom of the swing, what is the direction of the net force acting on tarzan?

The net force is pointing up the vine towards the center of its swinging. This is the centripetal force. Gravity is also acting on Tarzan pulling directly downward.

Answer:

Towards the center

Explanation:

Tarzan undergoes circular motion so the net force toward the center acting on him is required. Thus, the tension in the vine is greater than the gravitational force on Tarzan.

COLLEGE

An engine extracts 441.3kJ of heat from the burning of fuel each cycle, but rejects 259.8 kJ of heat (exhaust, friction,etc) during each cycle. What is the thermal efficiency of the engine?

Answer:

- The thermal efficiency is 0.4113.

Explanation:

We know that the thermal efficiency is the ratio of work done by the engine over the heat taken

Now, how much work the engine do in a cycle?

We know that the work done in a cycle must be equal to the heat taken minus the heat rejected

So, the thermal efficiency will be:

Putting the values of the problem