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3 years ago

PLEASE HELP! I'LL GIVE BRAINLEST

Physics

1 answer:

Alexxx [7]3 years ago

4 0

Answer:

Explanation:

The answer is C. Both options are correct

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The theory that the Earth's crust and part of the upper mantle are broken into sections that move on a fluid layer of the mantle

VMariaS [17]

I most sure about c but could be wrong

6 0

3 years ago

If 27 J of work are needed to stretch a spring from 15 cm to 21 cm and 45 J are needed to stretch it from 21 cm to 27 cm, what i

kupik [55]

Answer:

9 cm.

Explanation:

The energy used for stretch the spring from $15 cm$ to $21 cm$ will be , $E_{1}=27J$

The energy used for stretch the spring from $21 cm$ to $27 cm$ will be , $E_{2}=45J$

using the energy of spring formula ,we find that

$27 = \frac{1}{2}K((21-L^{2})-(15-L^{2}))$

$45 = \frac{1}{2}K((27-L^{2})-(21-L^{2}))$

Dividing both the equation will get,

$\frac{3}{5}=\frac{(21-L)^{2}-(15-L)^{2}}{(27-L)^{2}-(21-L)^{2}}\\5((21-L)^{2}-(15-L)^{2})=3((27-L)^{2}-(21-L)^{2})\\3(729 - 54L + L^{2}- 441 + 42L - L^{2} ) = 5(441 - 42L + L^{2} - 225 + 30L - L^{2} )\\3(288 - 12L) = 5(216 - 12L)\\24L = 216\\L = 9 cm$

Therefore, the natural length of the spring is, 9 cm.

4 0

3 years ago

A stone is dropped from rest from the top of a cliff into a pond below. If its initial height is 10 m, what is its speed when it

Brut [27]

Answer:

14 m/s

Explanation:

The motion of the stone is a free fall motion, so an accelerated motion with constant acceleration g = 9.8 m/s^2 towards the ground. So, we can use the following SUVAT equation:

$v^2 -u^2 = 2gh$

where

v is the final speed of the stone as it reaches the water

u = 0 is the initial speed

g = 9.8 m/s^2 is the acceleration

h = 10 m is the distance covered by the stone

Solving for v, we find

$v=\sqrt{u^2+2gh}=\sqrt{0+2(9.8 m/s^2)(10 m)}=14 m/s$

8 0

3 years ago

Which of the following was an effect of the French Revolution?

lozanna [386]

Answer: C. the elimination of special privileges for members of the first and second estates

Explanation:

The French Revolution was a period of political change in France. The French Revolution led to the proclamation of the first French Republic, radical political and social change, creation of constitutional monarchy, formation of the French consulate etc.

From the options given, the effect of the French Revolution was the the elimination of special privileges for members of the first and second estates. Therefore, the correct option is C.

5 0

3 years ago

The third floor of a house is 8m above street level. How much work is needed to move a 136kg refrigerator to the third floor?

jonny [76]

m = Mass of the refrigerator to be moved to third floor = 136 kg

g = Acceleration due to gravity by earth on the refrigerator being moved = 9.8 m/s²

h = Height to which the refrigerator is moved = 8 m

W = Work done in lifting the object

Work done in lifting the object is same as the gravitational potential energy gained by the refrigerator. hence

Work done = Gravitation potential energy of refrigerator

W = m g h

inserting the values

W = (136) (9.8) (8)

W = 10662.4 J

8 0

3 years ago

PLEASE HELP! I'LL GIVE BRAINLEST​

PLEASE HELP! I'LL GIVE BRAINLEST