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Xelga [282]
3 years ago
12

Picture showing four cards in a row with labels 'First animal appears on land', 'First life form appears in the sea', 'First roc

ks formed on Earth', and 'First flowering plants appear on land'.
A student arranged the four cards sequentially in a row on the basis of the periods when the events occurred. The card showing the earliest event was placed on the extreme left. Which of these cards was placed first in the row?
Physics
1 answer:
sasho [114]3 years ago
3 0
The answer would be 'First rocks formed on Earth'.
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A 1.50-m string of weight 0.0125 N is tied to the ceiling at its upper end, and the lower end supports a weight W. Ignore the ve
Natalka [10]

Answer:

Explanation:

mass of string = .0125 / 9.8

= 1.275 x 10⁻³ kg

Length of string l = 1.5 m .

m = mass per unit length

= ( .1.275 / 1.5) x 10⁻³ kg/m

m = .85 x 10⁻³ kg/m

wave equation: y(x,t) = (8.50 mm)cos(172 rad/m x − 4830 rad/s t)

compare with equation of wave

y(x,t) = Acos(K x − ω t)

ω ( angular velocity ) = 4830 rad/s

k = 172 rad/m

Velocity = ω / k

= 4830/172 m /s

= 28.08 m /s

velocity of wave = \sqrt{\frac{W}{m } }

28.08 = \sqrt{\frac{W}{.85\times10^{-3} } }

788.48 =  W / .85 X 10⁻³

W = 670 x  10⁻³ N .

c ) wave length

wave length =2π  / k

= 2 x 3.14 / 172

= .0365 m

no of wave lengths over whole length of string

= 1.5 / .0365

= 41

d )

equation for waves traveling down the string

= (8.50 mm)cos(172 rad/m x + 4830 rad/s t)

5 0
3 years ago
When reading the printout from a laser printer, you are actually looking at an array of tiny dots.
solniwko [45]

Answer:

The value is y  = 3.097 * 10^{-5} \  m

Explanation:

From the question we are told that

The diameter of the pupil is d_p  =  4.2 \ mm  =  4.2 *10^{-3} \  m

The distance of the page from the eye d =  29 \  cm  =  0.29 \  m

The wavelength is \lambda  =  500 \ nm =  500 *10^{-9} \  m

The refractive index is n_r =  1.36

Generally the minimum separation of adjacent dots that can be resolved is mathematically represented as

y  = [ \frac{1.22 *  \lambda }{d_p * n_r } ]* d

         y  = [ \frac{1.22 *  500 *10^{-9} }{4.2 *10^{-3} * 1.36} ]* 0.29

         y  = 3.097 * 10^{-5} \  m

7 0
3 years ago
A car and a truck collide in an intersection and the merged wreck continues along. During the collision. both kinetic energy and
Vilka [71]

Answer:

C. Momentum is conserved but not kinetic energy.

Explanation:

This case represents an entirely inelastic collision, that is, a collision between the car and the truck that reduces total kinetic energy of the entire system, whereas linear momentum is conserved. Hence, correct answer is C.

5 0
3 years ago
This chemical equation represents a ______________ reaction.
Ede4ka [16]

Answer:

you didnt put anything

Explanation:

7 0
3 years ago
Read 2 more answers
You are standing at the top of a cliff that has a stairstep configuration. There is a vertical drop of 7 m at your feet, then a
Zolol [24]

Answer:

1. v = 6.67 m/s

2. d = 9.54 m

Explanation:

1. To find the horizontal velocity of the rock we need to use the following equation:

d = v*t \rightarrow v = \frac{d}{t}    

<u>Where</u>:

d: is the distance traveled by the rock

t: is the time

The time can be calculated as follows:

t = \sqrt{\frac{2d}{g}}

<u>Where:</u>

g: is gravity = 9.8 m/s²

t = \sqrt{\frac{2d}{g}} = \sqrt{\frac{2*7 m}{9.8 m/s^{2}}} = 1.20 s

Now, the horizontal velocity of the rock is:

v = \frac{d}{t} = \frac{8 m}{1.20 s} = 6.67 m/s      

Hence, the initial velocity required to barely reach the edge of the shell below you is 6.67 m/s.          

2. To calculate the distance at which the projectile will land, first, we need to find the time:

t = \sqrt{\frac{2d}{g}} = \sqrt{\frac{2*(7 m + 3 m)}{9.8 m/s^{2}}} = 1.43 s

So, the distance is:

d = v*t = 6.67 m/s*1.43 s = 9.54 m    

Therefore, the projectile will land at 9.54 m of the second cliff.

I hope it helps you!        

7 0
3 years ago
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