PHYSICS
HIGH SCHOOL

Answer:

Answer:

V_avg = 578.6364 miles/hr

Explanation:

Given:

- The distance between airports d = 1,273 miles

- The time taken for the flight t = 2.2 hr

Find:

The average speed of the jet

Solution:

- The average speed of the jet is given by V_avg:

V_avg = Total distance traveled / Total time

V_avg = 1273 / 2.2

V_avg = 578.6364 miles/hr

Answer: Speed : distance divide by time . 1273/2.2 = ...

Use calculator .

Use calculator .

HIGH SCHOOL

It is almost time for the summer Olympics. The Olympic hammer throw is a throwing event where the object is to throw a heavy metal ball attached to a wire and handle. The name hammer throw comes from an older contest where men threw a sledge hammer. The hammer have different weights, ranging from 16 pounds down to 8 pounds. Imagine there are four hammers to throw: 16, 12, 10, and 8 pounds. You can pick any hammer to win the contest. Which would be the best choice if you want to throw the hammer the farthest you can?

We have four weights 16, 12, 10, and 8 pounds

We have F = m x a => F = m x v/t => F = m x s/t^2.

If the force exerted is same on all the weights, mass that is weight is inversely proportional to distance.

So the lighter the weight, longest will be the distance. So the answer here is 8 pounds.

We have F = m x a => F = m x v/t => F = m x s/t^2.

If the force exerted is same on all the weights, mass that is weight is inversely proportional to distance.

So the lighter the weight, longest will be the distance. So the answer here is 8 pounds.

We have four weights 16, 12, 10, and 8 poundsWe have F = m x a => F = m x v/t => F = m x s/t^2.If the force exerted is same on all the weights, mass that is weight is inversely proportional to distance.So the lighter the weight, longest will be the distance. So the answer here is 8 pounds.

MIDDLE SCHOOL

Which statement best explains why teens burn more energy than adults? A) Teens digest food differently than adults.

B) Teens have a higher metabolism than adults.

C) Teens are more active than adults.

D) A teen's body is still growing and building muscles and bones, while adults have stoped growing.

I bet it's D, cuz that makes more sense, but I'd like to know if that what you agree with: )

It could be A or B.... but i think its B

He There! :D

The answer here would be B. Teens have a higher metabolism than adults

Having a higher metabolism means you burn through energy quicker, the higher the metabolism the more energy you burn

Teens tend to have a higher metabolism than adults because as your body matures your metabolism slows and is a little harder to keep track with which is why so many adults have to "diet" to stay in shape.

Teens also tend to do more exercising than adults because they move around a lot more.

So I will reinstate that your correct answer here should be B. Teens have a higher metabolism than adults.

~Davonte

The answer here would be B. Teens have a higher metabolism than adults

Having a higher metabolism means you burn through energy quicker, the higher the metabolism the more energy you burn

Teens tend to have a higher metabolism than adults because as your body matures your metabolism slows and is a little harder to keep track with which is why so many adults have to "diet" to stay in shape.

Teens also tend to do more exercising than adults because they move around a lot more.

So I will reinstate that your correct answer here should be B. Teens have a higher metabolism than adults.

~Davonte

HIGH SCHOOL

On a trip to the Colorado Rockies, you notice that when the freeway goes steeply down a hill, there are emergency exits every few miles. These emergency exits are straight ramps which leave the freeway and are sloped uphill. They are designed to stop runaway trucks and cars that lose their brakes on downhill stretches of the freeway even if the road is covered with ice. You are curious, so you stop at the next emergency exit to take some measurements. You determine that the exit rises at an angle of 10o from the horizontal and is 100m long. What is the maximum speed of a truck that you are sure will be stopped by this road, even if the frictional force of the road surface is negligible?

Answer:

The maximum speed that the truck can have and still be stopped by the 100m road is the speed that it can go and be stopped at exactly 100m. Since there is no friction, this problem is similar to a projectile problem. You can think of the problem as being a ball tossed into the air except here you know the highest point and you are looking for the initial velocity needed to reach that point. Also, in this problem, because there is an incline, the value of the acceleration due to gravity is not simply g; it is the component of gravity acting parallel to the incline. Since we are working parallel to the plane, also keep in mind that the highest point is given in the problem as 100m. Solving for the initial velocity needed to have the truck stop after 100m, you should find that the maximum velocity the truck can have and be stopped by the road is 18.5 m/s.

Explanation:

MIDDLE SCHOOL

What is the thermal energy of an object? A.its total temperature

B.the total kinetic energy of its particles

C.the total potential energy of its particles

D.the total kinetic and potential energies of its particles

The answer is D

Hope this helps

Hope this helps

Answer:

d

Explanation:

HIGH SCHOOL

You roll a marble down a playground slide that starts level, then curves downward, and finally curves very gradually upward so that it's level again at the end. Where along its travel does the marble experience its greatest acceleration? its greatest speed?

Answer:

Greatest acceleration at end of downward curve before the upward curve

Greatest speed at end of upward curve before the final plain level

Explanation:

Notice that the marble will experience highest speed and highest acceleration at different points.

Now, part by part we can examine.

It is obvious that at initial level or plain, no acceleration occurs but speed is same. Now, when the first curve occur, it is downward, so marble will start to accelerate. It is assumed that it is inclined motion, So acceleration will be

a = gsinФ(1)

Now Ф(1) is the angle this inclined motion is creating with x plane.

Now on the second curve, notice that this curve is slightly upward but not plain, so still, there is increase in speed, but acceleration will reduce because again

a = gsinФ(2)

but Ф(1) greater than Ф(2)

so acceleration at downward curve will be greater than acceleration at upward curve. But speed will be increasing before the final straight level come. Because when straight level starts, it will be only friction against the inertia of marble and both will be acting along x axis but in different directions, so, speed just before this final straight level will be highest.

HIGH SCHOOL

The density of pine is generally about 0.5g/cm3. What is the mass of an 800cm3 piece of pine?

M=400g hope it helps

MIDDLE SCHOOL

Is resistance greater or lesser in a hotter wire?

The answer would be greater.

As the temperature of a common ordinary piece of wire increases, its resistance increases too.

HIGH SCHOOL

Suppose you are watching a video of a space mission and hear that a 2-pound hammer weighs 1 pound on the planet's surface. At approximately what rate would the hammer accelerate if it is dropped on the planet? **I have the correct answer. can someone explain the math part of it? 4.9 m/s^2 I need someone to work it out. PLEASE!

The "weight" of anything is

(the object's mass)

times

(the acceleration of gravity in the place where the object is).

Let's back up for a second, and consider why the hammer is called

"a 2-pound hammer" in the first place ?

That's because on Earth, where the hammer has spent all of

its life so far, and where it is acted upon by Earth's gravity, it

weighs 2 pounds.

The acceleration of gravity on Earth is 9.8 m/s².

(weight) = (mass) x (acceleration of gravity)

so

2 pounds = (mass) x (9.8 m/s²) .

Look at that equation.

If the left side suddenly becomes 1 pound instead of 2 pounds,

then something on the right side must also have suddenly become

1/2 of what it used to be. It's not the mass ... mass doesn't change.

So it must have been the acceleration that changed by half ...

it became (1/2 of 9.8) = 4.9 m/s² .

COLLEGE

Estimate the first three standing-wave frequencies of the vocal tract. use v=344m/s. (the answers are only an estimate, since the position of lips and tongue affects the motion of air in the vocal tract.)

Vocal tract behaves like a stopped pipe.

The fundamental frequency for a stopped pipe is given with the following formula:

Higher harmonics are simply:

Keep in mind that the stopped pipe produces only odd harmonics.

Lenght of a human vocal tract is 17cm(for males, females have slightly shorter vocal tract). We can now calculate the answers.

Now we can calculate higher harmonics:

The fundamental frequency for a stopped pipe is given with the following formula:

Higher harmonics are simply:

Keep in mind that the stopped pipe produces only odd harmonics.

Lenght of a human vocal tract is 17cm(for males, females have slightly shorter vocal tract). We can now calculate the answers.

Now we can calculate higher harmonics: