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3 years ago

Assertion: A normal human eye can see clearly all the objects below and above 25 cm

Physics

1 answer:

katen-ka-za [31]3 years ago

6 0

Answer: d)

Both Assertion and Reason are false

Explanation:

The least distance of distinct vision for normal human beings is 25 cm. That is,

normal eye can not be able to see clearly the objects placed closer than 25 Centimetre.

Havong an Assertion that normal human eye can see clearly all the objects below and above 25 cm is false. And since the assertion is false, the reason behind it is invalid. Therefore, having a reason that the human eye has the capacity to suitable adjust the focal length of its lens to a certain extent is also false.

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An object's angular momentum is proportional to its __________. An object's angular momentum is proportional to its __________.

ozzi

An object's angular momentum is proportional to its moment of inertia.

Option D

<u>Explanation:</u>

Momentum is the measure of an object's movement with respect to its mass and velocity. So it is determined as the product of mass and velocity. An object moving in linear motion, will experience linear momentum.

Similarly, if an object moves in circular motion, then the momentum will be angular momentum. So it is measured as the product of moment of inertia with angular velocity.

$L = Iw$

Here L is the angular momentum , I is the moment of inertia and ω is the angular velocity.

Thus, the angular momentum is directly proportional to the moment of inertia.

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3 years ago

A CD has a mass of 17 g and a radius of 6.0 cm. When inserted into a player, the CD starts from rest and accelerates to an angul

Stells [14]

Answer:

τ =9.41 * 10⁻⁴ N*m

Explanation:

Kinematics of the CD

The CD rotates with constant angular acceleration and its angular acceleration is calculated as follows:

$\alpha = \frac{\omega_{f}- \omega_{i}}{t}$ Formula (1)

Where:

α : angular acceleration. (rad/s²)

ωf: final angular velocity (rad/s)

ωi : initial angular velocity (rad/s)

t = time interval (s)

Data

ωf= 20 rad/s

ωi =0

t = 0.65 s.

Calculating of the angular acceleration of the CD

We replace data in the formula (1)

$\alpha = \frac{20 -0}{0.65}$

α = 30.77 rad/s²

Newton's second law in rotation:

F = ma has the equivalent for rotation:

τ = I * α Formula (2)

where:

τ : It is the net torque applied to the body. (N*m)

I : it is the moment of inertia of the body with respect to the axis of rotation (kg*m²)

α : It is angular acceleration. (rad/s²)

Calculating of the moment of inertia of the CD

The moment of inertia of a disk with respect to an axis perpendicular to the plane and passing through its center is calculated by the following formula:

I = (1/2) M*R² Formula (3)

Data

M= 17 g = 17/1000 kg = 0.017 kg : CD mass

R= 6.0 cm= 6/100 m = 0.06 m : CD radius

We replace data in the formula (3) :

I = (1/2) ( 0.017 kg)*(0.06 m)² = 3.06 * 10⁻⁵ kg*m²

Calculating of the net torque acting on the CD

Data

α = 30.77 rad/s²

I = 3.06 * 10⁻⁵ kg*m²

We replace data in the formula (2) :

τ = I * α

τ =( 3.06 * 10⁻⁵ kg*m²) * (30.77 rad/s²)

τ =9.41 * 10⁻⁴ N*m

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3 years ago

In electricity distribution, why is low voltage safer for consumers?

RUDIKE [14]

Answer:

Explanation:

The transmission lines contain about 2500 volts. It is dangerous enough to get zapped by 120 volts. Think what 20 times that much would do to you.

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What is the average speed of a boy who jogs 250 meters in 110 seconds

Ede4ka [16]

2.27 mps repeating.

This is the last question ill ever answer here. Thanks for being the last.

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Answer:

i think it d

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