Ask question

Ask question

All categories

3 years ago

10

19) Which two structures are not found in animal cells? A) vacuoles and ribosomes B) chloroplasts and ribosomes C) cell walls an

d chloroplasts D) endoplasmic reticulum and cell walls

2 answers:

LUCKY_DIMON [66]3 years ago

7 0

The answer to your question is: C) Cell walls and chloroplasts

(I hope this helps!)

Molodets [167]3 years ago

5 0

Cell walls and Chloroplasts

You might be interested in

Kinetic Energy RE-

tatiyna

Answer:

1) The potential energy, P.E = 4527.6 J

2) The mass, m = 1.28 kg

3) The height of the bell, h = 4.31 m

4) The kinetic energy, K.E = 385 J

5) The velocity of the car, V = 22.53 m/s

6) The mass of the car, m = 17.59 kg

Explanation:

1) The height of the hill, h = 21 m

The carriage with a baby has mass of, m = 22 kg

The potential energy,

P.E = mgh

= 22 x 9.8 x 21

= 4527.6 J

2) The height of the platform, h = 20 m

The P.E of the cinder block, P.E = 250 J

The mass,

m = P.E / gh

= 250 / (9.8 x 20)

= 1.28 kg

3) The mass of the bell, m = 18 kg

The P.E of the bell, P.E = 760 J

The height of the bell,

h = P.E/mg

= 760 / 18 x 9.8

= 4.31 m

4) The mass of the runner, m = 55 kg

The velocity of the runner, v = 14 m/s

The kinetic energy,

K.E = ½ mv²

= ½ x 55 x 14

= 385 J

5)The kinetic energy of the car, K.E = 69,759 J

The mass of the car, m = 275 kg

The velocity of the car,

V = √(2K.E/m)

V = √( 2 x 69759 / 275)

= 22.53 m/s

6) The velocity of the car, v = 38 m/s

The kinetic energy of the car, K.E = 12700 J

The mass of the car,

m = 2 K.E/ v²

= 2 x 12700 / 38²

m = 17.59 kg

8 0

3 years ago

What is the difference between Drift current & Diffusion current ?

dsp73

The main difference between the drift current and diffusion current is the corresponding reaction of the semiconductor materials in the electric fields. In electric fields, when semiconductor material's movement go along with the direction of the electric field it is called drift current, but when it tends to go from high concentrated area to lower concentrated area then it is diffusion current.

8 0

3 years ago

Which statement best describes the superposition principle?

avanturin [10]

Explanation:

A.) If two in-phase waves arrive simultaneously at a point, their amplitudes add up.

7 0

3 years ago

Myopia is a condition of the eye where the crystalline lens focuses the light rays to a position between the lens and the retina

aliya0001 [1]

Answer: concave lens

Explanation:

Myopia is a condition of the eye where someone can only see near distant object clearly but not far distant object.

Myopia is corrected using concave lens (diverging) in order to diverge the rays entering the eye thereby allowing the rays to be focused properly on the retina.

4 0

3 years ago

A dime is placed in front of a concave mirror that has a radius of curvature R = 0.40 m. The image of the dime is inverted and t

andrew11 [14]

Answer:

distance between the dime and the mirror, u = 0.30 m

Given:

Radius of curvature, r = 0.40 m

magnification, m = - 2 (since,inverted image)

Solution:

Focal length is half the radius of curvature, f = $\frac{r}{2}$

f = $\frac{0.40}{2} = 0.20 m$

Now,

m = - $\frac{v}{u}$

- 2 = - $\frac{v}{u}$

$\frac{v}{u}$ = 2 (2)

Now, by lens maker formula:

$\frac{1}{f} = \frac{1}{u} + \frac{1}{v}$

$\frac{1}{v} = \frac{1}{f} - \frac{1}{u}$

v = $\frac{uf}{u - f}$ (3)

From eqn (2):

v = 2u

put v = 2u in eqn (3):

2u = $\frac{uf}{u - f}$

2 = $\frac{f}{u - f}$

2(u - 0.20) = 0.20

u = 0.30 m

6 0

3 years ago