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1 year ago

Why is platinum used sparingly in technological applications?

1 answer:

5 0

Platinum is very light and strong alloy, though is has many uses, what prevents is economic consideration, is that platinum is very expensive. It is being in jewelry. Platinum is also used in the chemical industry as a catalyst for the production of nitric acid.silicone benzene. Platinum compounds is also used as important chemotherapy drugs used to treat cancer.

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2. A pebble is dropped down a well and hits the water 1.5 s later. Using the equations for motion with constant acceleration, de

kow [346]

Answer:

S = 11.025 m

Explanation:

Given,

The time taken by the pebble to hit the water surface is, t = 1.5 s

Acceleration due to gravity, g = 9.8 m/s²

Using the II equations of motion

S = ut + 1/2 gt²

Here u is the initial velocity of the pebble. Since it is free-fall, the initial velocity

u = 0

Therefore, the equation becomes

S = 1/2 gt²

Substituting the given values in the above equation

S = 0.5 x 9.8 x 1.5²

= 11.025 m

Hence, the distance from the edge of the well to the water's surface is, S = 11.025 m

3 0

2 years ago

A steel ball bearing with a radius of 1.5 cm forms an image of an object that has been placed 1.1 cm away from the bearing’s sur

Nonamiya [84]

Answer:

Check the explanation

Explanation:

given

R = 1.5 cm

object distance, u = 1.1 cm

focal length of the ball, f = -R/2

= -1.5/2

= -0.75 cm

let v is the image distance

use, 1/u + 1/v = 1/f

1/v = 1/f - 1/u

1/v = 1/(-0.75) - 1/(1.1)

v = -0.446 cm <<<<<---------------Answer

magnification, m = -v/u

= -(-0.446)/1.1

= 0.405 <<<<<<<<<---------------Answer

The image is virtual

The image is upright

given

R = 1.5 cm

object distance, u = 1.1 cm

focal length of the ball, f = -R/2

= -1.5/2

= -0.75 cm

let v is the image distance

use, 1/u + 1/v = 1/f

1/v = 1/f - 1/u

1/v = 1/(-0.75) - 1/(1.1)

v = -0.446 cm <<<<<---------------Answer

magnification, m = -v/u

= -(-0.446)/1.1

= 0.405 <<<<<<<<<---------------Answer

Kindly check the diagram in the attached image below.

5 0

1 year ago

Consider a ball rolling around in a circular path on the inner surface of a cone. the weight of the ball is shown by the vector

zimovet [89]

Answer:

option 2 is righttttt.................

5 0

1 year ago

Which phenomenon can only be explained by assuming that light is quantized

Serjik [45]

<h2>Answer: The Photoelectric Effect</h2>

Light can be considered as a wave or as particles, in this context Einstein proposed that light behaves like a stream of particles called <u>photons</u> with an energy, in order to correctly explain the photoelectric effect.

This fenomenom consists in the emission of electrons (electric current) that occurs when light falls on a metal surface <u>under certain conditions. </u>

So, if we consider light as a stream of photons and each of them has energy, this energy is able to pull an electron out of the crystalline lattice of the metal and communicate, in addition, a <u>kinetic energy</u>.

This means the photoelectric effect can only be explained based on the corpuscular model of light, that is, light is quantized.

3 0

2 years ago

A 0.200-kg mass is attached to the end of a spring with a spring constant of 11 N/m. The mass is first examined (t = 0) when the

inn [45]

Answer:

a) x (t) = 0.3187 cos (7.416 t + 1.008) , b) v = -2,363 sin (7,416 t + 1,008)

c) a = - 17.52 cos (7.416t + 1.008)

Explanation:

The spring mass system creates a harmonic oscillator that is described by the equation

x = Acos (wt + φ)

Where is the amplitude, w the angular velocity and fi the phase

a) Let's reduce the SI system

x = 17.0 cm (1 m / 100 cm) = 0.170 m

The angular velocity is given by

w = √ (k / m)

w = √ 11 / 0.200

w = 7.416 rad / s

Let's look for the terms of the equation with the data for time zero (t = 0 s)

0.170 = A cos φ

Body speed can be obtained by derivatives

v = dx / dt

v = -A w sin (wt + φ)

2.0 = -A 7.416 sin φ

Let's write the two equations

0.170 = A cos φ

2.0 / 7.416 = -A sin φ

Let's divide those equations

tan φ= 2.0 / (7.416 0.170)

φ= tan⁻¹ (1,586)

φ= 1.008 rad

We calculate A

A = 0.170 / cos φ

A = 0.170 / cos 1.008

A = 0.3187 m

With these values we write the equation of motion

x (t) = 0.3187 cos (7.416 t + 1.008)

b) the speed can be found by derivatives

v = dx / dt

v = - 0.3187 7.416 sin (7.416 t +1.008)

v = -2,363 sin (7,416 t + 1,008)

c) the acceleration we look for conserved

a = dv / dt

a = -2,363 7,416 cos (7,416 t + 1,008)

a = - 17.52 cos (7.416t + 1.008)

6 0

2 years ago