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3 years ago

4. Why are cells important?

Physics

1 answer:

Blizzard [7]3 years ago

6 0

Answer:

Cells provide structure for the body, take in nutrients from food and carry out important functions. ... These organelles carry out tasks such as making proteins?, processing chemicals and generating energy for the cell.

Explanation:

Cells are the basic structures of all living organisms.

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A 10 kg mass stretches a spring 70 cm in equilibrium. Suppose a 2 kg mass is attached to the spring, initially displaced 25 cm b

NARA [144]

Answer:

Explanation:

1. Find spring constant k. From a free body diagram, you will get the forces on the 10 kg mass, with a displacement d. It will be gravity pulling the mass down and the spring force pulling the mass up. The 10 kg mass is in equilibrium. The resulting equation will be:

$F = m_1a = kd - m_1g = 0 => m_1g = kd => k = \frac{m_1g}{d}$

2. Use the result from 1. to find the equations of motion. In general they are given by:

$x(t) = Acos(\omega t + \phi), v(t) = -\omega Asin(\omega t + \phi)$ , where ω is: $\omega = \sqrt{\frac{k}{m_2}}=\sqrt{\frac{m_1g}{m_2d}}$

To find the amplitude A and the phase angle Ф, use the given initial conditions:

m₂ = 2 kg, x(0) = -0.25 m, v(0) = 2m/s

$-0.25 = Acos(\phi)\\2 = -\omega Asin(\phi)= -\sqrt{\frac{m_1g}{m_2d}}Asin(\phi)\\-0.24 = Asin(\phi)$

Solving for Ф:

$\frac{0.24}{0.25}=tan(\phi) => \phi = 0.76$

Solving for A:

$-0.25 = Acos(\phi) => A = -\frac{0.25}{cos(\phi)}=-0.35$

The equation for x(t) is now:

$x(t) = -0.35 cos(\sqrt{\frac{m_1g}{m_2d}t} +0.76)$

The frequency f is given by: $f = \frac{\omega}{2\pi}$

The period T is given by: $T = \frac{2\pi}{\omega}$

8 0

3 years ago

An astronaut is rotated in a horizontal centrifuge at a radius of 5.0 m. (a) What is the astronaut’s speed if the centripetal ac

sergeinik [125]

Explanation:

Given that,

Radius of circular path, r = 5 m

Centripetal acceleration, $a=7g\ m/s^2$

(a) Let v is the astronaut’s speed. The formula for the centripetal acceleration is given by :

$a=\dfrac{v^2}{r}$

$v=\sqrt{ar}$

$v=\sqrt{7\times 9.8\times 5}$

v = 18.5 m/s

(b) Let T denotes the time period. It is given by :

$T=\dfrac{2\pi r}{v}$

$T=\dfrac{2\pi \times 5}{18.5}$

T = 1.69 s

Let N is the number of revolutions. So,

$N=\dfrac{60}{1.69}=35.5\ rev/min$

So, the number of revolutions per minute is 35.5

Hence, this is the required solution.

8 0

4 years ago

How much force must a locomotive exert on a 12840-kg boxcar to make it accelerate forward at 0.490 m/s2?

ddd [48]

Data given:

m=12840kg

a=0.490m/s²

Formula:

F=ma

Solution:

F= 12840kg×0.490m/s²

F=6291.6N

6 0

3 years ago

(please help asap)

OLEGan [10]

Answer:

A. Yard

Explanation:

Should be correct lol :)

6 0

3 years ago

Read 2 more answers

"A uniform cylinder of mass M and radius R is rolling without slipping. The velocity of its center of mass is v. What is the cyl

Goshia [24]

Answer:

Explanation:

Given

mass of cylinder is M

radius R

velocity of center of mass is v

As there is no slipping therefore cylinder will rotate as well as translate

Moment of inertia of cylinder $I=\frac{MR^2}{2}$

Kinetic Energy of cylinder $K.E.=\frac{1}{2}Mv^2$

Rotational energy $R.E.=\frac{1}{2}I\omega ^2$

for rolling

$v=\omega \times r$

where $\omega =angular\ velocity\ of\ cylinder$

$R.E.=\frac{1}{2}\times \frac{MR^2}{2}\times (\frac{v}{R})^2=\frac{1}{4}Mv^2$

Total kinetic Energy $=\frac{1}{2}Mv^2+\frac{1}{4}Mv^2=\frac{3}{4}Mv^2$

6 0

3 years ago