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DiKsa [7]
2 years ago
9

Why do scientists believe that dark matter exists even though it cannot be seen?

Physics
1 answer:
poizon [28]2 years ago
3 0
Because although they cannot see it, they can see it's influence on objects that can be seen, and it's effects.
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A certain digital camera having a lens with focal length 7.50 cmcm focuses on an object 1.70 mm tall that is 4.70 mm from the le
Crank

Answer:

a. 7.62cm

b. Real and inverted

c. 2.76 cm

d. 3450

Explanation:

We proceed as follows;

a. the lens equation that relates the object distance to the image distance with the focal length is given as follows;

1/f = 1/p + 1/q

making q the subject of the formula;

q = pf/p-f

From the question;

p = 4.70m

f = 7.5cm = 0.075m

Substituting these, we have ;

q = (4.7)(0.075)/(4.7-0.075) = 0.3525/4.625 = 0.0762 = 7.62 cm

b. The image is real and inverted since the image distance is positive

c. We want to calculate how tall the image is

Mathematically;

h1 = (q/p)h0

h1 = (7.62/4.70)* 1.7

h1 = 2.76 cm

d. We want to calculate the number of pixels that fit into this image

Mathematically:

n = h1/8 micro meter

n = 2.76cm/8 micro meter = 2.76 * 10^-2/8 * 10^-6 = 3450

3 0
3 years ago
Does kinetic energy decrease as speed increase
leva [86]
Potential energy increases as speed decreases. Kinetic increases when speed increases.
6 0
2 years ago
A 500 N weight sits on the small piston of a hydraulic machine. The small piston has area 2.0 cm2. If the large piston has area
Ghella [55]

Answer:

d. 10000N

Explanation:

When a force (F_1) is exerted on the smaller area piston (A_1), the pressure that originates therein is transmitted to the larger area piston(A_2). According to Pascal's principle the pressure on the smallest piston (P_1=\frac{F_1}{A_1}) will be equal to the pressure on the largest piston (P_2=\frac{F_2}{A_2}):

\frac{F_1}{A_1}=\frac{F_2}{A_2}\\F_2=F_1\frac{A_2}{A_1}\\F_2=500N\frac{40cm}{2cm}\\F_2=10000N

7 0
3 years ago
A 5 kg bowling ball with a velocity of +10 m/s collides with a stationary 2 kg bowling pin. If the ball's final velocity is +8 m
Whitepunk [10]

Answer:

<h2>The pin's final velocity is 5m/s</h2>

Explanation:

Step one:

given data

mass of ball m1=5kg

initial velocity of ball u1=10m/s

mass of pin m2=2kg

initial velocity of pin u2= 0m/s

final velocity of ball v2=8m/s

final velocity of pin v2=?

Step two:

The expression for elastic collision is given as

m1u1+m2u2=m1v1+m2v2

substituting we have

5*10+2*0=5*8+2*v2

50+0=40+2v2

50-40=2v2

10=2v2

divide both sides by 2

v2=10/2

v2=5m/s

The pin's final velocity is 5m/s

3 0
3 years ago
Help me please Which of the following statements best describes the atoms and molecules that make up a glass
Nataliya [291]

Answer:

The correct option is;

The atoms and molecules of the liquid water are moving, while the atoms and molecules of the glass are not moving

Explanation:

Matter that exist in the liquid or gaseous state consist of molecules that move freely about in the entire containing medium for gas, while the molecules move freely  in the portion of the container occupied by the fluid in the case of liquid fluids

However, the molecules of a solid are fixed within the current shape of the solid and are only free to vibrate within a fixed location and the allow the passage of subatomic particles such as electrons

As such, the glass cup being a solid, consists of molecules fixed in space, while the liquid water consists of molecules which can translate within the portion of the volume of the glass filled with the water.

7 0
3 years ago
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