I really need help on this

The mass after a physical change, such as ice melting into water, stays the same a. -true b. -false.

kupik [55]

Answer:

Yes, it can be destroyed.The total amount of matter (atoms) before and after a chemical reaction (change), remains the same.

Explanation:

hope this helps

3 0

3 years ago

A rock is thrown upward from level ground in such a way that the maximumheight of its flight is equal to its horizontal rangeR.

Snowcat [4.5K]

A) The vertical component of velocity v is taking the rock to a height

Vertical component = $vsin\theta$
The time taken to reach maximum height = $\frac{vsin\theta}{g}$
So total time of rocks flight = $\frac{2vsin\theta}{g}$
Range of rock is due to the horizontal component of velocity = $vcos\theta$
Range = $\frac{2*v*sin\theta*v*cos\theta}{g}$ = $\frac{2*v^2*sin\theta*cos\theta}{g}$
Maximum height = $\frac{g*t^2}{2}$ = $\frac{v^2*sin^2\theta}{2*g}$
Since range = maximum height
We have $\frac{2*v^2sin\theta*cos\theta}{g} = \frac{v^2*sin^2\theta}{2*g}$
$tan\theta = 4$
$\theta = 75.96^0$
So when angle of projection is $\theta = 75.96^0$ range is equal to maximum height reached.
b) We have range = $\frac{2*v^2*sin\theta*cos\theta}{g}$ = $\frac{2*v^2*sin2\theta}{g}$
Maximum of range is reached when $\theta = 45^0$
Maximum range = $\frac{2*v^2}{g}$
c) For range to be equal to maximum height only condition is $tan\theta = 4$ , it does not depend upon acceleration due to gravity and velocity. That angle is a constant.

5 0

3 years ago

Which of the moon’s properties prevents it from being pulled inward by earth?

bekas [8.4K]

Answer:

Inertia

Explanation:

Inertia is the inherent property of an object to remain in its state of rest or motion without being disturbed.

6 0

4 years ago

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True or false: Alcohol can cause an uncontrolled ________ of the eyes, making good vision almost impossible

svetlana [45]

Twitching of the eye

5 0

3 years ago

If the index of refraction of a lens is 1.5, how fast does light travel in the lens?

Len [333]

The speed of light in a material is given by:
$v= \frac{c}{n}$
where
$c=3 \cdot 10^8 m/s$ is the speed of light in vacuum
n is the refractive index of the material

The lens in this problem has a refractive index of n=1.50, therefore the speed of light in the lens is
$v= \frac{c}{n}= \frac{3 \cdot 10^8 m/s}{1.50}=2 \cdot 10^8 m/s$

And the correct answer is C).

5 0

3 years ago

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