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3 years ago

As a projectile moves down its vertical velocity is positive?

1 answer:

7 0

When YOU start working on a problem, if the question doesn't TELL you which direction is positive and which is negative, then YOU get to decide before you start solving the problem.

MOST often, people use positive for UP and negative for DOWN, just because that's the way we naturally think of 'up' and 'down'. But there's no law. If you want to, you can just as well call up 'negative' and call down 'positive'.

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Explain what happens as an object moves through each phase of matter.<br><br> ASAP PLEASE ????????

Lisa [10]

Explanation:

gas vibrate and moves freely at high speeds, liquid vibrate, move about, and slide past each other. solid vibrate (jiggle) but generally do not move from place to place

hope it helps you

3 0

3 years ago

Which two surfaces have the lowest coefficient of friction

jok3333 [9.3K]

Answer:

Explanation:

As an example, ice on steel has a low coefficient of friction – the two materials slide past each other easily – while rubber on pavement has a high coefficient of friction – the materials do not slide past each other easily. The coefficients of friction ranges from near 0 to greater than 1.

5 0

2 years ago

A vector is parallel to the y axis, what is it x component?<br>

slavikrds [6]

Answer:

Explanation:

A vector is parallel to the y axis .

Let its magnitude be A . So the vector can be represented as A j .

where i and j are unit vectors in x and y axis direction .

The x component of A j will be dot product of A j with i

The x component of A j = A j . i

= A x 0 [ Since j . i = 0 ]

= 0

4 0

3 years ago

A cat’s crinkle ball toy of mass 15g is thrown straight up with an initial speed of 3m/s . Assume in this problem that air drag

Readme [11.4K]

Answer:

(a)0.0675 J

(b)0.0675 J

(d)0.0675 J

(e)-0.0675 J

(f)0.459 m

Explanation:

15g = 0.015 kg

(a) Kinetic energy as it leaves the hand

$E_k = \frac{mv^2}{2} = \frac{0.015*3^2}{2} = 0.0675 J$

(b) By the law of energy conservation, the work done by gravitational energy as it rises to its peak is the same as the kinetic energy as the ball leave the hand, which is 0.0675 J

(d) The gravitational energy at peak point would also be the same as 0.0675J

(e) In this case as the reference point is reversed, we would have to negate the original potential energy. So the potential energy as the ball leaves hand is -0.0675J

(f) Since at the maximum height the ball has potential energy of 0.0675J. This means:

mgh = 0.0675

0.015*9.81h = 0.0675

h = 0.459 m

The ball would reach a maximum height of 0.459 m

4 0

3 years ago

The center of mass is

PolarNik [594]

D is the best answer. In many physics problems we treat an extended object as if it were a point with the same mass located at the center of mass.

5 0

3 years ago