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xenn [34]
4 years ago
5

HELP!!!!!! PLEASE!! I WILL GIVE 25 POINTS!!!!

Physics
2 answers:
Zolol [24]4 years ago
8 0

3 is B my dude and the reason nobody answered is because thousands of questions are asked every day. So not every question can be answered. It doesn't have to do with being lazy.  

Novay_Z [31]4 years ago
5 0

1) C) Ben is right because the electricity from the light is transformed into heat and light.

Explanation:

The Law of Conservation of Energy states that energy cannot be created nor destroyed, but only transformed.

In this particular example, energy is not destroyed. In fact, the electrical energy (produced, for instance, by the battery inside the torchlight) is converted into light (electromagnetic wave) and heat (thermal energy). So, Ben is right, because energy is just transformed into other types of energy.

2) D) Neither is completely right. Shawn is partly correct since kinetic energy depends on mass, but Greg is also partly right since it also depends on speed.

Explanation:

The kinetic energy of an object is given by:

K=\frac{1}{2}mv^2

where m is the mass of the object and v its speed. From the formula, we see that neither Shawn nor Greg is completely right, because the kinetic energy depends both on the mass and the speed, and:

- Greg only told about the speed

- Shawn only told about the mass

3) B) Dan's sister was correct because Dan's legs touched the car seats. That is an indicator of heat transfer by conduction.

Explanation:

Conduction is the method of heat transfer that occurs between two solid objects, when they are in contact with each other, and it is due to the collisions between the molecules of the two objects: when colliding, the molecules of the hotter object transfer part of their kinetic energy to the molecules of the colder object.

In this case, Dan legs are in contact with the car seat (which is at higher temperature), so heat is transferred from the seat to Dan legs by conduction.

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A 5.0 g coin is placed 15 cm from the center of a turntable. The coin has static and kinetic coefficients of friction with the t
Kaylis [27]

Answer:

Angular speed will reach 6.833rad/s before the coin starts slipping

Explanation:

There is no question but I'll asume the common one: Calculate the speed of the turntable before the coin starts slipping.

With a sum of forces:

Ff = m*a

Ff=m*V^2/R

At this point, friction force is maximum, so:

\mu*N=m*V^2/R

\mu*m*g=m*V^2/R

Solving for V:

V=\sqrt{\mu*g*R}

V=1.025 m/s

The angular speed of the turntable will be:

ω = V/R = 6.833 rad/s   This is the maximum speed it can reach before the coin starts slipping.

7 0
3 years ago
A steady beam of alpha particles (q = + 2e, mass m = 6.68 × 10-27 kg) traveling with constant kinetic energy 22 MeV carries a cu
cluponka [151]

Answer:

Explanation:

q = 2e = 3.2 x 10^-19 C

mass, m = 6.68 x 10^-27 kg

Kinetic energy, K = 22 MeV

Current, i = 0.27 micro Ampere = 0.27 x 10^-6 A

(a) time, t = 2.8 s

Let N be the alpha particles strike the surface.

N x 2e = q

N x 3.2 x 10^-19 = i t

N x 3.2 x 10^-19 = 0.27 x 10^-6 x 2.8

N = 2.36 x 10^12

(b) Length, L = 16 cm = 0.16 m

Let N be the alpha particles

K = 0.5 x mv²

22 x 1.6 x 10^-13 = 0.5 x 6.68 x 10^-27 x v²

v² = 1.054 x 10^15

v = 3.25 x 10^7 m/s

So, N x 2e = i x t

N x 2e = i x L / v

N x 3.2 x 10^-19 = 2.7 x 10^-7 x 0.16 / (3.25 x 10^7)

N = 4153.85

(c) Us ethe conservation of energy

Kinetic energy = Potential energy

K = q x V

22 x 1.6 x 10^-13 = 2 x 1.5 x 10^-19 x V

V = 1.17 x 10^7 V

5 0
3 years ago
A red ball is thrown down with an initial speed of 1.6 m/s from a height of 25 meters above the ground. Then, 0.4 seconds after
Radda [10]

Answer:

1. v =  22.2 m/s

2. t = 2.25 seconds

3. h = 27.05 m

4. t = 1.16 seconds

Explanation:

The questions involve motion under the influence of gravity

1. Using the formula v² = u² + 2gh

where u = 1.6 m/s; g= 9.81 m/s²; h = 25 m; v = ?

v² = (1.6)² + 2 * 9.81 * 25

√v² = √493.06

v =  22.2 m/s

2. Using h = ut + 1/2 gt²

where h = 25 m; u = 0 (since velocity on reaching the ground is zero); g = 9.81 m/s²; t = ?

therefore, h = 1/2 gt²

making t subject of the formula, t = √ (2*h /g)

t = √ (2 * 25 / 9.81)

t = 2.25 seconds

3. Time of travel for the blue ball, t = 2 - 0.4 = 1.6s

using h = ut - gt²

u = 24 m/s; t = 1.6 s; g = 9.81 m/s²

note: since the ball is travelling against gravity, g is negative

h = 24 * 1.6 - 11/2 * 9.81 * 1.6²

h = 38.4 - 12.55 = 25.85 m

since height above the ground is 1.2 m,

total height h = 25.85 m + 1.2 m

h = 27.05 m

4. Let the time of travel of the red ball be t seconds.

So the time of travel of the blue ball = (t - 0.4) seconds.

Both the balls are at the same height :

25 - s = 1.2 + h  where s & h are the displacements of the red & the blue ball respectively.

25 - (ut + 1/2 gt2) = 1.2 + (ut - 1/2 gt2)

25 - (1.6 t + 0.5 * 9.8 t²) = 1.2 + (24(t-0.4) - 0.5*9.8*(t-0.4)²)

solving the equation above for the time after which both the balls are at the same height.

25 - 1.6t - 4.9t² = 1.2 + 24t - 9.6 - 4.9t² + 3.92t - 0.784

collecting like terms

(25 - 1.2 + 9.6 + 0.784) = (24 + 3.92 + 1.6) * t  

t = 34.184 / 33.44

t = 1.16 seconds

6 0
3 years ago
1. True or False: All sound happens through vibration.<br> A True<br> B False
Genrish500 [490]

Answer:

True

Explanation:

Sound is all about vibrations.

The source of a sound vibrates, bumping into nearby air molecules which in turn bump into their neighbor's, and so forth.

4 0
3 years ago
Read 2 more answers
What do you need to verify in a patient's profile? A. Name, history of illness, medication, dose, strength, frequency B. Name, a
Lubov Fominskaja [6]
Hey there friend :)

I would go with Choice A

Sorry if wrong :(

Have a Fabulous day!
3 0
4 years ago
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