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3 years ago

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2. Why was it important to examine both the color and the streak of your minerals? Think about streak and explain why it’s calle

d a mineral’s “true color”. Answer in at least 2 sentences.

1 answer:

horrorfan [7]3 years ago

3 0

<span>Some minerals might have similar color, but different streaks. Others might have the same streak color, but different colors</span>

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Tides occur in oceans but not in lakes why?

lawyer [7]

Answer:

Explanation:

Tides occur mainly in oceans because that is basically one huge body of water that is free to move all over the earth. Lakes and rivers do not cover enough area to have their water be moved significantly by gravity, or in other words, to have tides.

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3 years ago

Read 2 more answers

Which speed(s) is/are below the sound barrier in air? A. 257 m/s B. 1,030 m/s C. 10 m/s

Assoli18 [71]

The answers are A&C. please mark me brainliest

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3 years ago

A toy cannon uses a spring to project a 5.38-g soft rubber ball. The spring is originally compressed by 5.08 cm and has a force

yawa3891 [41]

(a) 1.43 m/s

We can solve this problem by using the law of conservation of energy.

The initial total energy stored in the spring-mass system is

$E=U=\frac{1}{2}kx^2$

where

k = 7.91 N/m is the spring constant

$x=5.08 cm = 0.0508 m$

Substituting,

$E=\frac{1}{2}(7.91)(0.0508)^2=0.0102 J$

The final kinetic energy of the ball is equal to the energy released by the spring + the work done by friction:

$E+W_f=K$

where

$K_f=\frac{1}{2}mv^2$ is the kinetic energy of the ball, with

$m=5.38 g = 5.38\cdot 10^{-3} kg$ being the mass of the ball

v being the final speed

$W_f = -F_f d$ is the work done by friction (which is negative since the force of friction is opposite to the motion), where

$F_f = 0.0323 N$ is force of friction

d = 14.5 cm = 0.145 m is the displacement

Substituting,

$W_f = -(0.0323)(0.145)=-4.68\cdot 10^{-3} J$

So, the kinetic energy of the ball as it leaves the cannon is

$K_f = E+W_f = 0.0102 - 4.68\cdot 10^{-3}=0.00552 J$

And so the final speed is

$v=\sqrt{\frac{2K_f}{m}}=\sqrt{\frac{2(0.00552)}{0.00538}}=1.43 m/s$

(b) +5.08 cm

The speed of the ball is maximum at the instant when all the elastic potential energy stored in the spring has been released: in fact, after that moment, the spring does no longer release any more energy, so the kinetic energy of the ball from that moment will start to decrease, due to the effect of the work done by friction.

The elastic potential energy of the spring is

$U=\frac{1}{2}kx^2$

And this has all been released when it becomes zero, so when x = 0 (equilibrium position of the spring). However, the spring was initially compressed by 5.08 cm, so the ball has maximum speed when

x = +5.08 cm

with respect to the initial point.

(c) 1.78 m/s

The maximum speed is the speed of the ball at the moment when the kinetic energy is maximum, i.e. when all the elastic potential energy has been released.

As we calculated in part (a), the total energy released by the spring is

E = 0.0102 J

The work done by friction here is just the work done to cover the distance of

d = 5.08 cm = 0.0508 m

Therefore

$W_f = -(0.0323)(0.0508)=-1.64\cdot 10^{-3} J$

So, the kinetic energy of the ball at the point of maximum speed is

$K_f = E+W_f = 0.0102 - 1.64\cdot 10^{-3}=0.00856 J$

And so the final speed is

$v=\sqrt{\frac{2K_f}{m}}=\sqrt{\frac{2(0.00856)}{0.00538}}=1.78 m/s$

7 0

3 years ago

In zoes egg experiment which two forces are balanced to keep it from hitting the pan

alexgriva [62]

Answer:

The forces of push and pull

Explanation:

In the egg drop experiment, the egg is balanced on top of a toilet paper tube and balanced on a pan. The pan itself is placed on top of a glass of water. When the experimenter uses his hands to push the pan, the force of gravity pulls the egg downwards making it move down, right into the glass of water.

So the two forces which are applied in opposite directions are;

1. The force of push applied horizontally by the hand when it pushes the pan away, and

2. The force of pull caused by gravity which makes the egg move vertically downwards.

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3 years ago

A 150-newton force, applied to a wooden crate at an angle of 30° above the horizontal, causes the crate to travel at constant ve

koban [17]

Answer is in the photo. I can't attach it here, but I uploaded it to a file hosting. link below! Good Luck!

tinyurl.com/wtjfavyw

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3 years ago