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3 years ago

11

1. Johnny wants to know where the water line is in a dark well. He drops a penny into the well and counts until he hears the pen

ny hit the water. He counts exactly 3 seconds. How far down is the water line?

1 answer:

777dan777 [17]3 years ago

8 0

Answer:

3 feet down

Explanation:

i think

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Someone pushes on a rock and measures the net force acting on it is 147 N and acceleration to be 7.5m/s2.What is the weight of t

kogti [31]

Some1 pushes u and then u defend your self

7 0

3 years ago

A chicken flaps off the roof of the henhouse with a velocity of 4.5 m/s north. The chicken lands 2.8 seconds later. If a hungry

katrin2010 [14]

I think that it might be B?
Tell me if im wrong

8 0

3 years ago

1. If an object that stands 3 centimeters high is placed 12 centimeters in front of a plane

igor_vitrenko [27]

Answer:

1. 12 cm

2. 0.133 m

3. 0.03 m

4. Plane mirror

Virtual image

Upright

Behind the mirror

The same size as the object

Concave mirror when the object is located a distance greater than the focal length from the mirror's surface

Real image

Inverted image

In front of the the mirror

Diminished when the object is beyond the center of curvature

Same size as object when the object is placed at the center of curvature

Enlarged when the object is placed between the center of curvature of the mirror and the focus of the mirror

Concave mirror when the object is located a distance less than the focal length from the mirror's surface

Virtual image

Upright image

Behind the the mirror

Enlarged

Convex mirror

Type = Virtual image

Appearance = Upright image

Placement = Behind the mirror

Size = Smaller than the object

Explanation:

1. For plane mirror, since there is no magnification, the virtual image distance from the mirror = object distance from the mirror = 12 cm behind the mirror

2. The height of the object = 0.3 m

The distance of the object from the mirror = 0.4 meters

Height of image formed = 0.1 meter

We have;

$Magnification, \ m = \dfrac{Image \ height }{Object \ height } = \dfrac{Image \ distance \ from \ mirror }{Object\ distance \ from \ mirror }$

$m = \dfrac{0.1}{0.3 } = \dfrac{Image \ distance \ from \ mirror }{0.4 }$

Image distance from the mirror = 0.1/0.3×0.4 = 2/15 = 0.133 m

Image distance from the mirror = 0.133 m

3. $m = \dfrac{Image \ height}{0.10 } = \dfrac{0.06 }{0.20 }$

The image height = 0.06/0.2×0.1 = 3/100 = 0.03 meter

The image height = 0.03 meter

4. Plane mirror

Type = Virtual image

Appearance = Upright image with the left transformed to right

Placement = Behind the mirror

Size = The same size as the object

Concave mirror when the object is located a distance greater than the focal length from the mirror's surface

Type = Real image

Appearance = Inverted image

Placement = In front of the the mirror

Size = Diminished when the object is beyond the center of curvature

Same size as object when the object is placed at the center of curvature

Enlarged when the object is placed between the center of curvature of the mirror and the focus of the mirror

Concave mirror when the object is located a distance less than the focal length from the mirror's surface

Type = Virtual image

Appearance = Upright image

Placement = Behind the the mirror

Size = Enlarged

Convex mirror

Type = Virtual image

Appearance = Upright image

Placement = Behind the mirror

Size = Smaller than the object.

3 0

4 years ago

A model rocket weighing 4.9 N launches from a pad. How much work does the little rocket engine do in the first 4 meters

USPshnik [31]

Answer:

Work done by the little rocket engine = 19.6 Joules.

Explanation:

We know that work = force x displacement.

Force = weight of rocket = 4.9 N

Displacement = 5 meter.

So work done by the little rocket engine = Weight of rocket x displacement.

Work done by the little rocket engine = 4.9 x 4 = 19.6 J

Work done by the little rocket engine = 19.6 Joules.

5 0

3 years ago

According to Care-stream's operating manual, what is the acceptable range of exposure indicators?

Aleks [24]

Answer:

correct option is C. 1700 - 2300

Explanation:

solution

according to Care stream, exposure indicators provide the technical adequancy incident radiations on the x ray

and we muse care stream formula that is

Exposure Index EI = 1000 × $log_{10} (mR)$ + 2000

here 1 mR = 2000 EI

and 2 mR = 2300 EI

and 3 mR = 1700 EI

so here acceptable range of exposure indicators is 1700 - 2300

correct option is C. 1700 - 2300

5 0

3 years ago