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Alekssandra [29.7K]
3 years ago
12

Suzy drops a rock from the roof of her house. Mary sees the rock pass her 2.7 m tall window in 0.129 sec. From how high above th

e top of the window was the rock dropped? The acceleration of gravity is 9.8 m/s 2 . Answer in units of m.
Physics
1 answer:
vladimir1956 [14]3 years ago
8 0

Answer:

h = 22.35 m

Explanation:

given,

initial speed of the rock,u = 0 m/s

length of the window,l = 2.7 m

time taken to cross the window,t = 0.129 s

Speed of the rock when it crosses the window

v = \dfrac{l}{t}

v = \dfrac{2.7}{0.129}

  v = 20.93 m/s

height of the building above the window

using equation of motion

v² = u² + 2 g h

20.93² = 0² + 2 x 9.8 x h

h = 22.35 m

Hence, the height of the building above the top of window is equal to h = 22.35 m

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A 150kg person stands on a compression spring with spring constant 10000n/m and nominal length of 0.50.what is the total length
Ivahew [28]

Answer:

<em>The total length of the spring would be 0.65 m</em>

Explanation:

The Concept

Hooke's law evaluates the increment of  spring in relation to the force acting on the body. Hooke's law states that for a spring undergoing deformation, the  force applied is directly proportional to the deformation experienced by the spring. Hooke's law is represented thus;

F = k x ..................1

where F is the force applied to the spring

k is the spring constant

x is the spring stretch or extension

Step by Step Calculations

We have to obtain x before adding it to the nominal length, We make x the subject formula in equation 1;

x = F/k

but F = m x g

so, x = (m x g)/k

given that, the mass of the person m =150 kg

g is the acceleration due to gravity = 9.81 m/s^{2}

k is the spring constant = 10000 N/m

then x = (9.81 m/s^{2} x 150 kg)/10000 N/m

x = 0.14715 m

the extension experienced by the spring after the compression is 0.14715 m

The total length of the spring would be;

L = 0.14715 m + 0.5 m = 0.64715

L ≈  0.65 m

Therefore the total length of the spring would be 0.65 m

4 0
3 years ago
Some cities now implement signal lights designed to specifically apply to _____ rather than motorized vehicles.
dmitriy555 [2]

The correct answer is C; Bicycles.

Further Explanation:

In major cities, in the United States, have implemented signal lights specifically designed for bicycle riders. The riders also have their own designated bike lanes in many large cities. Drivers in vehicles, are to give the right of way to people on bicycles.

Bicycle riders are to follow the same laws and laws specifically for the riders or they can face fines and tickets.

Learn more about bicycle laws at brainly.com/question/8934107

#LearnwithBrainly

7 0
3 years ago
15 PTS! HELP! BRAINLIEST!
vodka [1.7K]
I cant do all but I can do number 4
      When force moves ur leg u start skatin and when that happenes ur using a lot of force to move
3 0
3 years ago
The 10-kg uniform rod is pinned at end
Anton [14]
Supposing that the spring is un stretched when θ = 0, and has a toughness of k = 60 N/m.It seems that the spring has a roller support on the left end. This would make the spring force direction always to the left 
Sum moments about the pivot to zero. 
10.0(9.81)[(2sinθ)/2] + 50 - 60(2sinθ)[2cosθ] = 0 98.1sinθ + 50 - (120)2sinθcosθ = 0 98.1sinθ + 50 - (120)sin(2θ) = 0 
by iterative answer we discover that 
θ ≈ 0.465 radians 
θ ≈ 26.6º 
3 0
3 years ago
An 16.00-kg object is suspended by a rope at some height, h if the object has a potential energy of 900.01j what is the objects
qwelly [4]

Answer:

5.740 m

Explanation:

PE = mgh

900.0 J = (16.00 kg) (9.8 m/s²) h

h = 5.740 m

5 0
3 years ago
Read 2 more answers
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