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3 years ago

In which situation is maximum work considered to be done by a force?

Physics

1 answer:

umka2103 [35]3 years ago

7 0

Answer:

A) When the angle between the Force (F) and Displacement (x) is 0°, because, Work done (W) is directly proportional to the Cosine of the Angle between the Force applied and the resultant displacement of the subject.

W = F•x cos ∅

If ∅ = 0°,

W = F•x ===> Maximum Work Done.

If ∅ = 45°,

W = F•x/√2

If ∅ = 90°,

W = 0

If ∅ = 180°,

W = –F•x ===> Minimum Work Done.

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1.How does gravity change your weight?<br><br> 2.How do force work in nature?

kodGreya [7K]

In a stronger gravitational field a given mass will have a larger weight.

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3 years ago

A block of mass 0.1 kg is attached to a spring of spring constant 21 N/m on a frictionless track. The block moves in simple harm

bogdanovich [222]

Answer:

A) 2.75 m/s B) 0.1911 m C) 0.109 s

Explanation:

mass of block = M =0.1 kg

spring constant = k = 21 N/m

amplitude = A = 0.19 m

mass of bullet = m = 1.45 g = 0.00145 kg

velocity of bullet = vᵇ = 68 m/s

as we know:

Angular frequency of S.H.M = ω₀ = $\sqrt\frac{k}{M}$

= $\sqrt\frac{21}{0.1}$

= 14.49 rad/sec

<h3>A) Speed of the block immediately before the collision:</h3>

displacement of Simple Harmonic Motion is given as:

$x = A sin (\omega t + \phi)\\$

Differentiating this to find speed of the block immediately before the collision:

$v=\frac{dx}{dt}= A\omega_{o} cos (\omega_{o}t =\phi}\\$

As bullet strikes at equilibrium position so,

φ = 0

t= 2nπ

⇒ cos (ω₀t + φ) = 1

⇒ $v= A\omega_{o}$

$v=(.19)(14.49)\\v= 2.75 ms^{-1}$

<h3>B) If the simple harmonic motion after the collision is described by x = B sin(ωt + φ), new amplitude B:</h3>

S.H.M after collision is given as :

$x= Bsin(\omega t + \phi)$

To find B, consider law of conservation of energy

$K.E = P.E\\K.E= \frac{1}{2}(m+M)v^{2} \\P.E = \frac{1}{2} kB^{2}$

$\frac{m+M}{k} v^{2} = B^{2} \\B =\sqrt\frac{m+M}{k} v\\B = \sqrt\frac{.00145+0.1}{21} (2.75)\\B = .1911m$

<h3>C) Time taken by the block to reach maximum amplitude after the collision:</h3>

Time period S.H.M is given as:

$T=2\pi \sqrt\frac{m}{k}\\ for given case\\m= m=M\\then\\T=2\pi \sqrt\frac{m+M}{k}$

Collision occurred at equilibrium position so time taken by block to reach maximum amplitude is equal to one fourth of total time period

$T=\frac{\pi }{2}\sqrt\frac{m+M}{k} \\T=0.109 sec$

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3 years ago

Suppose the electric field between two parallel plates kept constant but the distance between them is tripled. What happens to t

alukav5142 [94]

Answer:

The voltage increases by a factor of three.

Explanation:

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sergey [27]

True the magnitude is the velocity of speed

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Hi:) why do metals have free electrons? anyone able to explain the conduction part as well? Thanks!

Karo-lina-s [1.5K]

Metals have free electrons due to the bonding in metallic substances.

In a metal there are strong attractive forces between the nuclei and the valance electrons.

Positively charged metal nuclei form a lattice (a cube like structure) each metal atom provides one or more valance electrons <u>that are free to move throughout the lattice</u> The electrons are attracted to the positively charged nuclei but not one individual nuclei, this is called non-directional bonding since it occurs in all directions.

Now all metals are conductive becuase of the free to move (delocalised) electrons. Since the valance electrons are free to move throughout the lattice they are able to carry a charge. (Ionic solids cannot since the ionic solids form a tightly packed lattice with cations and anions which have no free moving electrons, electrons have to be able to move to carry a charge)

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3 years ago