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zavuch27 [327]
2 years ago
7

A 30-kg child stands at one end of a floating 20-kg canoe that is 5.0-m long and initially at rest in the water. The child then

slowly walks to the other end of the canoe. How far does the canoe move in the water, assuming water friction is negligible
Physics
1 answer:
Yuliya22 [10]2 years ago
5 0

Answer:

The canoe move 3 m in water.  

Explanation:

Given that,

Mass of the child, m = 30 kg

Mass of canoe, M = 20 kg

Length of canoe, L = 5 m

  • Since initially the boat is floating, its center of mass was at rest. So, when child moves on the boat from one end to the other end, the boat moves in opposite direction in such a way that the displacement of their center of mass remains at rest.            
  • Let x be the displacement of canoe in opposite direction to the motion of child, therefore  displacement of child is L - x

So, the displacement of the center of mass is given by :

d_{cm}=\dfrac{m(L-x)-Mx}{m+M}\\\\0=\dfrac{m(L-x)-Mx}{m+M}\\\\m(L-x)-Mx=0\\\\30(5-x)-20x=0\\\\x=3\ m

So, the canoe move 3 m in water.                                              

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When light energy hits the retina, the retinal changes from a _____ to a _____ configuration.
gayaneshka [121]

Answer:

Cis, Trans.

Explanation:

Rhodopsin also known as visual purple, pigment which contains sensory protein that helps to convert light into an electrical signal. Rhodopsin present in wide range of organisms from bacteria to vertebrates.

Rhodopsin is composed of opsin, and 11-cis-retinaldehyde which is derived from vitamin A. When the eye contact with light the 11-cis component converted to all trans-retinal, which results in the changes in configuration fundamental in the rhodopsin molecule.

5 0
2 years ago
Two thin lenses with a focal length of magnitude 12.0cm, the first diverging and the second converging, are located 9.00cm apart
attashe74 [19]

Answer:

Explanation:

b ) First is concave lens with focal length f₁ = - 12 cm .

object distance u = - 20 cm .

Lens formula

1 / v - 1 / u = 1 / f

1 / v + 1 / 20 = -1 / 12

1 / v =  - 1 / 20  -1 / 12

= - .05 - .08333

= - .13333

v = - 1 / .13333

= - 7.5 cm

first image is formed before the first lens on the side of object.

This will become object for second lens

distance from second lens = 7.5 + 9 = 16.5 cm

c )

For second lens

object distance u = - 16.5 cm

focal length f₂ = + 12 cm ( lens is convex )

image distance = v

lens formula ,

1 / v - 1 / u = 1 / f₂

1 / v + 1 / 16.5 = 1 / 12

1 / v =   1 / 12 -  1 / 16.5

= .08333- .0606

= .02273

v = 1 /  .02273

= 44 cm ( approx )

It will be formed on the other side of convex lens

distance from first lens

= 44 + 9 = 53 cm .

magnification by first lens = v / u

= -7.5 / -20 = .375 .

magnification by second lens = v / u

= 44 / - 16.5

= - 2.67

d )

total magnification

= .375 x - 2.67

= - 1.00125

height of final image

= 2.50 mm x 1.00125

= 2.503mm

e )

The final image will be inverted with respect to object  because total magnification is negative .

6 0
2 years ago
A 25kg child sits on one end of a 2m see saw. How far from the pivot point should a rock of 50kg be placed on the other side of
ivann1987 [24]

Answer:

a rock of 50kg should be placed =drock=0.5m from the pivot point of see saw

Explanation:

τchild=τrock  

Use the equation for torque in this equation.

(F)child(d)child)=(F)rock(d)rock)

The force of each object will be equal to the force of gravity.

(m)childg(d)child)=(m)rockg(d)rock)

Gravity can be canceled from each side of the equation. for simplicity.

 (m)child(d)child)=(m)rock(d)rock)  

Now we can use the mass of the rock and the mass of the child. The total length of the seesaw is two meters, and the child sits at one end. The child's distance from the center of the seesaw will be one meter.

(25kg)(1m)=(50kg)drock

Solve for the distance between the rock and the center of the seesaw.

drock=25kg⋅m50kg

drock=0.5m

6 0
2 years ago
A wave has a frequency of 34 Hz and a wavelength of 2.0 m. What is the speed of the wave? Use . A. 17 m/s B. 36 m/s C. 0.059 m/s
mel-nik [20]
F= (speed)/(wavelength)

Therefore, speed = Frequency x wavelength
  V = 68m/s
8 0
2 years ago
Read 2 more answers
A train goes up a hill with a 15º incline. If the train has constant speed of 22 m/s, what are the vertical and horizontal compo
Kobotan [32]
Any two-dimensional vector in cartesian (x,y) coordinates can be broken down into individual horizontal and vertical components using trigonometry. If a train goes up a hill with 15 degree incline at a speed of 22 m/s, the horizontal component is 22cos(15)=21.3 m/s and the vertical component is 22sin(15)=5.5 m/s. 
8 0
2 years ago
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