All categories

3 years ago

Whose main job is to help a plant cell make proteins A .endoplasmic reticulum B.chloroplasts C. Mitochondria

Physics

1 answer:

tatiyna3 years ago

3 0

Answer:

A .endoplasmic reticulum

Explanation:

Endoplasmic reticulum is the part of the plant cell that is responsible for the synthesis of proteins.

You might be interested in

Would u rather/content creator or a rap artist

BartSMP [9]

a content creator because if i was a rapper i probably wouldn't make good songs lol

7 0

2 years ago

Initially, a 2.00-kg mass is whirling at the end of a string (in a circular path of radius 0.750 m) on a horizontal frictionless

drek231 [11]

Answer:

$v_f = 15 \frac{m}{s}$

Explanation:

We can solve this problem using conservation of angular momentum.

The angular momentum $\vec{L}$ is

$\vec{L} = \vec{r} \times \vec{p}$

where $\vec{r}$ is the position and $\vec{p}$ the linear momentum.

We also know that the torque is

$\vec{\tau} = \frac{d\vec{L}}{dt} = \frac{d}{dt} ( \vec{r} \times \vec{p} )$

$\vec{\tau} = \frac{d}{dt} \vec{r} \times \vec{p} + \vec{r} \times \frac{d}{dt} \vec{p}$

$\vec{\tau} = \vec{v} \times \vec{p} + \vec{r} \times \vec{F}$

but, as the linear momentum is $\vec{p} = m \vec{v}$ this means that is parallel to the velocity, and the first term must equal zero

$\vec{v} \times \vec{p}=0$

$\vec{\tau} = \vec{r} \times \vec{F}$

But, as the only horizontal force is the tension of the string, the force must be parallel to the vector position measured from the vertical rod, so

$\vec{\tau}_{rod} = 0$

this means, for the angular momentum measure from the rod:

$\frac{d\vec{L}_{rod}}{dt} = 0$

that means :

$\vec{L}_{rod} = constant$

So, the magnitude of initial angular momentum is :

$| \vec{L}_{rod_i} | = |\vec{r}_i||\vec{p}_i| cos(\theta)$

but the angle is 90°, so:

$| \vec{L}_{rod_i} | = |\vec{r}_i||\vec{p}_i|$

$| \vec{L}_{rod_i} | = r_i * m * v_i$

We know that the distance to the rod is 0.750 m, the mass 2.00 kg and the speed 5 m/s, so:

$| \vec{L}_{rod_i} | = 0.750 \ m \ 2.00 \ kg \ 5 \ \frac{m}{s}$

$| \vec{L}_{rod_i} | = 7.5 \frac{kg m^2}{s}$

For our final angular momentum we have:

$| \vec{L}_{rod_f} | = r_f * m * v_f$

and the radius is 0.250 m and the mass is 2.00 kg

$| \vec{L}_{rod_f} | = 0.250 m * 2.00 kg * v_f$

but, as the angular momentum is constant, this must be equal to the initial angular momentum

$7.5 \frac{kg m^2}{s} = 0.250 m * 2.00 kg * v_f$

$v_f = \frac{7.5 \frac{kg m^2}{s}}{ 0.250 m * 2.00 kg}$

$v_f = 15 \frac{m}{s}$

8 0

3 years ago

An object with a mass of 375g is moving with a constant velocity. It has a force of -20 N applied to it. Determine the accelerat

olga55 [171]

Answer:

Explanation:

Convert the mass to kg:

375g = 375/1000kg = 0.375kg

F = ma

-20 = 0.375a

a = -20/0.375

a = -53

The object is accelerating at 53m/s/s backwards assuming that the forward motion is positive.

8 0

3 years ago

How is current related to voltage?

Tju [1.3M]

The relationship between current and voltage and resistance is described by ohlm's law. This equation i=v/r tells that the current i flowing through a circuit is directly proportional to the voltage v, and inversely proportional to resistance r. This desceibes the relationship of voltage, current and resistance.

8 0

3 years ago

Read 2 more answers

Which factors are used to calculate the kinetic energy of an object? Check all that apply. gravity velocity volume mass height

Sonja [21]

Quantities that determine the kinetic energy of a body are its mass and velocity

Answer: mass and velocity

Explanation:

The kinetic energy of a body is the energy possessed by an object by virtue of its motion. It is given by the equation

$k= \frac{1}{2}mv^2$

Where m represents mass of the body and v represents its velocity.

Two bodies of equal velocity but different mass the heavier body will have greater kinetic energy. When an object is at rest its velocity is equal to zero. Thus its kinetic energy will be zero. Hence it can be concluded that only moving bodies have kinetic energy.

Stationary objects placed at a height possess potential energy which is the energy by virtue of their position or configuration. The total mechanical energy of a system is the sum of potential and kinetic energy.

8 0

3 years ago

Read 2 more answers