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3 years ago

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What are the two ways to change the frictional force between two solid surfaces

1 answer:

Jet001 [13]3 years ago

3 0

Explanation:

I think The strength of the force of friction depends on two factors: <em><u>how hard the surfaces push together</u></em> and <em><u>the types of surfaces involved</u></em><em><u>.</u></em><em><u> </u></em>

Tell me if it's correct.

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Two parallel plates are a distance apart with a potential difference between them. A point charge moves from the negatively char

IgorC [24]

Answer:

K' = 1200 J

Explanation:

To find the kinetic energy you first take into account the formula for the kinetic energy of the charge:

$K=\frac{1}{2}mv^2$ = 800J (1)

m: mass of the charge

v: final speed of the charge when it reaches the positively charged plate.

Furthermore, you have that the acceleration of the charge is obtained by using the second Newton law:

$F=ma=qE\\\\a=\frac{qE}{m}$ (2)

a: acceleration

E: electric field

q: charge

The electric field between two parallel plates is V/d, being V the potential difference and d the separation between plates. You replace E in (2) and obtain:

$a=\frac{qV}{md}$

Next, you take into account the following formula for the calculation of the final speed of the charge:

$v^2=v_o^2+2ad\\\\v_o=0m/s\\\\v=\sqrt{\frac{2qVd}{md}}=\sqrt{\frac{2qV}{m}}$

Next, you replace this value of v in (1):

$K=\frac{1}{2}mv^2=\frac{1}{2}m(\frac{2qV}{m})=qV$ = 880J (3)

If the distance between plates is tripled, and the potential difference is halved, you have for the new final speed:

$v'^2=v'_o^2+2a(3d)\\\\v_o=0m/s\\\\v'=\sqrt{6ad}=\sqrt{6(\frac{q}{md})\frac{V}{2}d}=\sqrt{\frac{3qV}{m}}$

And the kinetic energy becomes:

$K'=\frac{1}{2}mv^2=\frac{1}{2}m(\frac{3qV}{m})=\frac{3}{2}qV$ (4)

You calculate the ratio between both kinetic energies K and K', that is, you divide equations (3) and (4), in order to find the new kinetic energy:

$K=qV=800J\\\\K'=\frac{3}{2}qV\\\\\frac{K}{K'}=\frac{qV}{3/2\ qV}=\frac{2}{3}\\\\K'=\frac{3}{2}K=\frac{3}{2}(800J)=1200J$

hence, the kinetic energy of the charge incresases to 1200J

4 0

3 years ago

An object has a velocity of 8 m/s and a kinetic energy of 480 J. What is the mass of the object? (Formula: ) KE=1/2mv squared

Julli [10]

Answer:15kg

Explanation:

kinetic energy=ke=480J

Velocity=v=8m/s

Mass=m

Ke=0.5 x m x v x v

480=0.5 x m x 8 x 8

480=32m

Divide both sides by 32

480/32=32m/32

15=m

Mass=15kg

5 0

3 years ago

Solids that have flat sides and a repeating pattern of atoms are called ______________.

DiKsa [7]

they are called crystals

7 0

4 years ago

A rocket burns fuel at a rate of 199 kg/s and exhausts the gas at a relative speed of 9 km/s. Find the thrust of the rocket. Ans

andreyandreev [35.5K]

Answer:

1.791 MN

Explanation:

Thrust of the rocket can be found using the relation

T = v.dm/dt, where

T = thrust off the rocket

v = speed of the rocket, 9 km/s = 9000 m/s

dm/dt = rate at which fuel burns, 199 kg/s

Substituting the values into the formula, we have

T = 9000 * 199

T = 1791000 N

T = 1.791*10^6 N

Since 1 MN = 10^6, thus

T = 1.791 MN

7 0

3 years ago

What do we call a solution that has as many ions as it can hold?

igomit [66]

A saturated solution

7 0

3 years ago

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