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3 years ago

A scientific hypothesis must be

1 answer:

3 0

A scientific hypothesis must be testable, but there is a much stronger requirement that a testable hypothesis must meet before it can really be considered <span>scientific</span>

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A 540 gram object is attached to a vertical spring, causing the spring’s length to change from 70 cm to 110 cm.

belka [17]

Answer:

Approximately $13\; {\rm N \cdot m^{-1}}$ (assuming that $g = 9.81\; {\rm N \cdot kg^{-1}}$ .)

Explanation:

Let $F_{\text{s}}$ denote the force that this spring exerts on the object. Let $x$ denote the displacement of this spring from the equilibrium position.

By Hooke's Law, the spring constant $k$ of this spring would ensure that $F_\text{s} = -k\, x$ .

Note that the mass of the object attached to this spring is $m = 540\; {\rm g} = 0.540\; {\rm kg}$ . Thus, the weight of this object would be $m\, g = 0.540\; {\rm kg} \times 9.81\; {\rm N \cdot kg^{-1}} \approx 5.230\; {\rm N}$ .

Assuming that this object is not moving, the spring would need to exert an upward force of the same magnitude on the object. Thus, $F_{\text{s}} = 5.230\; {\rm N}$ .

The spring in this question was stretched downward from its equilibrium by:

$\begin{aligned} x &= (70\; {\rm cm} - 110\; {\rm cm}) \\ &= (-40)\; {\rm cm} \\ &= (-0.40) \; {\rm m}\end{aligned}$ .

(Note that $x$ is negative since this displacement points downwards.)

Rearrange Hooke's Law to find $k$ in terms of $F_{\text{s}}$ and $x$ :

$\begin{aligned} k &= \frac{F_{\text{s}}}{-x} \\ &\approx \frac{5.230\; {\rm N}}{-(-0.40)\; {\rm m}} \\ &\approx 13\; {\rm N \cdot m^{-1}}\end{aligned}$ .

3 0

2 years ago

An optical disk drive in your computer can spin a disk up to 10,000 rpm (about 1045 rad / s). if a particular disk is spun at 79

NeX [460]

(i) |α| = 235.6rad.s / 0.502s = 469 rad/s²
(ii) tang a = α*r = 469rad/s² * 0.12m / 2*11 = 2.56 m/s²

4 0

3 years ago

What are stars made from

kap26 [50]

Stars are made of very hot gas. This gas is mostly hydrogen and helium, which are the two lightest elements. Stars shine by burning hydrogen into helium in their cores, and later in their lives create heavier elements.

3 0

4 years ago

(06.04 MC)<br> Which of the following best describes a human egg cell? (3 points)

Vinil7 [7]

Answer: A haploid cell formed in the female uterus

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3 years ago

what happens to the current in a circuit if the resitance of the components in the circuit is increased

Anit [1.1K]

Answer:

The current decreases.

Explanation:

Current and resistance are inversely proportional. The equation connecting current, resistance and voltage is $V = IR$ , where V is voltage, I is current and R is resistance.

Rearranging this equation, you get:

$I = \frac{V}{R}$

and

$R = \frac{V}{I}$

If the value of voltage in both equations remains constant, and the value of R decreases, the value of I will increase. Conversely, if in the second equation $R = \frac{V}{I}$ , the value of V remains constant the value of I decreases, then the value of R, resistance will increase.

Thus, it can be seen that the current will decrease as resistance increases and vice versa.

7 0

3 years ago