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4 years ago

The basis for defining the length of a day is the fact that question 21 options:

Physics

1 answer:

abruzzese [7]4 years ago

6 0

B.earth rotates on its axis in 24 hours; i.e., it rotates 15° of longitude per hour.

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after the car leaves the platform , gravity causes it to accelerate downward at a rate of 9.8 m/s2. what is the gravitational fo

alexandr1967 [171]

The gravitational force on the car is the force popularly known
as the car's "weight". Its magnitude is

(9.8 m/s²) times (the car's mass, in kilograms) .

The unit of this quantity is [newton] .

5 0

3 years ago

Technetium (Tc; Z = 43) is a synthetic element used as a radioactive tracer in medical studies. A Tc atom emits a beta particle

LenKa [72]

Answer : The de-Broglie wavelength of this electron, $0.101\AA$

Explanation :

The formula used for kinetic energy is,

$K.E=\frac{1}{2}mv^2$ ..........(1)

According to de-Broglie, the expression for wavelength is,

$\lambda=\frac{h}{mv}$

or,

$v=\frac{h}{m\lambda}$ ...........(2)

Now put the equation (2) in equation (1), we get:

$\lambda=\frac{h}{\sqrt{2\times m\times K.E}}$ ...........(3)

where,

$\lambda$ = wavelength = ?

h = Planck's constant = $6.626\times 10^{-34}Js$

m = mass of electron = $9.11\times 10^{-31}Kg$

K.E = kinetic energy = $4.71\times 10^{-15}J$

Now put all the given values in the above formula (3), we get:

$\lambda=\frac{6.626\times 10^{-34}Js}{\sqrt{2\times 9.11\times 10^{-31}Kg\times 4.71\times 10^{-15}J}}$

$\lambda=1.0115\times 10^{-11}m=0.101\AA$

conversion used : $(1\AA=10^{-10}m)$

Therefore, the de-Broglie wavelength of this electron, $0.101\AA$

7 0

3 years ago

Is NaCH an element? Why or why not?

amm1812

<span>NaCH is not an element, it is a compound. An element can be found and identified on the periodic table to elements. A compound is a combination of two of more elements. NaCH is composed of three elements: Na (sodium), C (carbon) and H (hydrogen), making it a compound.</span>

3 0

3 years ago

A mountain climber increases their height from 200 meters to 400 meters. What affect will this have on their potential energy?

Yanka [14]

Answer:

At 400 m the potential energy of the mountain climber doubled the initial value.

Explanation:

Given;

initial height of the mountain climber = 200 m

final height of the mountain climber, = 400 m

The potential energy of the mountain climber is calculated as;

Potential energy, P.E = mgh

At 200 m, P.E₁ = mg x 200 = 200mg

At 400 m, P.E₂ = mg x 400 = 400mg

Then, at 400 m, P.E₂ = 2 x 200mg = 2 x P.E₁

Therefore, at 400 m the potential energy of the mountain climber doubled the initial value.

4 0

3 years ago

A truck initially traveling at 20m/s decelerated at 1.50m/s2. Find (a) how long it takes to stop (b) how far it moves in that ti

finlep [7]

vf² = vi² + 2ad

vf = vi +at

vf = final velocity

vi = initial velocity

decelerated = a = - (negative)

a. stop ⇒ vf = 0

vf = vi+at

0 = 20 - 1.5t

1.5t=20

t = 13.3 s

b. vi = 20 m/s

0 = 20² - 1.5d

1.5d = 20²

1.5d = 400

d =266.67 m

c. d = vi.t -1/2at²

d = 20.3 - 1/2.1.5.3²

d = 53.25 m

5 0

3 years ago