For an object to slow down and stop due to friction while sliding across the floor which of the following would be true.

Sonja [21]

The second one is correct not sure about the first one sorry

8 0

3 years ago

What is the lift (in newtons) due to Bernoulli's principle on a wing of area 76 m2 if the air passes over the top and bottom sur

AveGali [126]

Answer:

So lift will be 30.19632 N

Explanation:

We have given area of the wing $a=76m^2$

We know that density of air $d=1.29kg/m^3$

Speed at top surface $v_2=290m/sec$ and speed at bottom surface $v_1=150m/sec$

According to Bernoulli's principle force is given by

$F=A\times d\times \frac{v_2^2-v_1^2}{2}=76\times 1.29\times \frac{290^2-150^2}{2}=3019632N$

4 0

3 years ago

Which list of properties of alternation current is the most likely reason it was chosen over direct current to provide electrici

Paraphin [41]

Answer:

- Direct current is a current in which electrons flow in one direction only

- Alternating current is a current in which the direction of the electron flow reverses periodically - so, half a cycle forward, half a cycle backward

There are several advantages of using alternating currents for the transmission of electricity across a country, over large distances. The main advantages are:

- The voltage of alternating currents can be easily increased/decreased by using transformers. For instance, a transformer is used at the beginning of the transmission line to increase the voltage (electricity is transmitted at high voltage in order to reduce dissipated power), and then another transformer is used before the electricity enters the houses, in order to decrease the voltage. Transformers only work with alternating currents.

- It is easy to interrupt the flow of an alternating current, because its value naturally becomes zero every half a cycle, so this is useful in case the current must be interrupted.

8 0

3 years ago

The average diameter of one tennis ball in a package of three is 6.8 cm. Which of the following is the combined volume of all th

Crank

We want to find the combined volume of 3 tennis balls. We will get that the combined volume is 493.7 cm^3

First, remember that for a sphere of diameter D, the volume is:

$V = \frac{4}{3}*3.14*(\frac{D}{2})^3$

Where 3.14 is pi.

Here we know that the average diameter of a tennis ball is 6.8cm, then we can replace that in the above equation to find the volume (in average) of a single tennis ball:

$V = \frac{4}{3}*3.14*(\frac{6.8cm}{2})^3 = 164.5 cm^3$

Now, in 3 balls of tennis, the combined volume will be 3 times the above one, this is:

$3*V = 3*164.5cm^3 = 493.7 cm^3$

If you want to learn more about volumes, you can read:

brainly.com/question/10171109

4 0

2 years ago

A ray is incident on a film of thickness t and the index of refraction n=1.6 at an angle θ = 35 degrees. Find the angle of refra

lidiya [134]

Answer

Given,

refractive index of film, n = 1.6

refractive index of air, n' = 1

angle of incidence, i = 35°

angle of refraction, r = ?

Using Snell's law

n' sin i = n sin r

1 x sin 35° = 1.6 x sin r

r = 21°

Angle of refraction is equal to 21°.

Now,

distance at which refractive angle comes out

d = 2.5 mm

α be the angle with horizontal surface and incident ray.

α = 90°-21° = 69°

t be the thickness of the film.

So,

$tan \alpha = \dfrac{t}{d/2}$

$tan 61^0 = \dfrac{t}{2.5/2}$

t = 2.26 mm

Hence, the thickness of the film is equal to 2.26 mm.

4 0

3 years ago