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dangina [55]
2 years ago
7

A person standing for a long time gets tired when he does not appear to do any work .why?​

Physics
1 answer:
Keith_Richards [23]2 years ago
6 0

Explanation:

A person standing still for a long time feels tired because the force of gravity acts on our body and puts stress on our muscles. so our muscles need energy to do work and keep body balanced and help to stand upright.

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The eyes of amphibians such as frogs have a much flatter cornea but a more strongly curved (almost spherical) lens than do the e
Lapatulllka [165]

Answer:

0.2cm towards the retina.

Explanation:

the focal length of the frog eye is

(1/f) = (1/10) + (1/0.8)

f = 0.74cm

Since the distance of the object is 15cm Hence

(1/0.74) = (1/15) + (1/V)

V = 0.78cm

Therefore the distance the retina is to move is

0.78cm - 0.8cm = 0.02cm towards the retina.

3 0
2 years ago
A compressed spring has 16.2 J of elastic potential energy when it is compressed 0.30 m. What is the spring constant of the spri
nikdorinn [45]
Elastic potential = 1/2 x constant x square of compression lenght
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7 0
2 years ago
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How much is the moment due to force P about point B. P(unit=N) vector is equal to (150i+260j ) and vector BA (unit=meter) is equ
artcher [175]

Answer:

The moment (torque) is given by the following equation:

\vec{\tau} = \vec{r} \times \vec{F}\\\vec{r} \times \vec{F} = \left[\begin{array}{ccc}\^{i}&\^j&\^k\\r_x&r_y&r_z\\F_x&F_y&F_z\end{array}\right] = \left[\begin{array}{ccc}\^{i}&\^j&\3k\\0.23&0.04&0\\150&260&0\end{array}\right] = \^k((0.23*260) - (0.04*150)) = \^k (53.8~Nm)

Explanation:

The cross-product between the distance and the force can be calculated using the method of determinant. Since the z-components are zero, it is easy to calculate.

4 0
2 years ago
Suppose you look out the window of a skyscraper and see someone throw a tomato downward from above your window. your window is a
photoshop1234 [79]
Formula for height 
<span> r(t) = a/2 t² + v₀ t + r₀
</span><span> where 
</span><span> a = acceleration = -32 ft/sec² (gravity) 
</span><span> v₀ = initial velocity 
</span><span> r₀ = initial height 
</span><span> r(t) = -16t² + v₀ t + r₀
</span> <span>Tomato passes window (height = 450 ft) after 2 seconds: 
</span><span> r(2) = 450
</span><span> -16(4) + v₀ (2) + r₀ = 450 
</span><span> r₀ = 450 + 64 - 2v₀ 
</span><span> r₀ = 514 - 2v₀ 
</span><span> Tomato hits the ground (height = 0 ft) after 5 seconds: 
</span><span> r(5) = 0 
</span><span> -16(25) + v₀ (5) + r₀ = 0
</span> r<span>₀ = 16(25) - 5v₀ 
</span><span> r₀ = 400 - 5v₀ 
</span><span> 
 r₀ = 514 - 2v₀ and r₀ = 400 - 5v₀
</span> <span>514 - 2v₀ = 400 - 5v₀
</span><span> 5v₀ - 2v₀ = 400 - 514
</span> <span>3v₀ = −114 
</span><span> v₀ = −38 
</span><span> Initial velocity = −38 ft/sec (so tomato was thrown down) 
</span><span> (initial height = 590 ft) </span>
4 0
2 years ago
Listed in the Item Bank are some important labels for sections of the image below. To find out more information about labels, so
gizmo_the_mogwai [7]

Answer:reactant,active site,enzyme below,substrate,products

Explanation:

5 0
2 years ago
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