Match the half life and time information to the percentage of radioactive isotope left.

Consider the following True/False statements:

Ainat [17]

Answer:

6) False

7) True

8) False

9) False

10) False

11) True

12) True

13) True

14) True

Explanation:

The spacing between two energy levels in an atom shows the energy difference between them. Clearly, B has a greater value of ∆E compared to A. This implies that the wavelength emitted by B is greater than A while B will emit fewer, more energetic photons.

When atoms jump from lower to higher energy levels, photons are absorbed. The kinetic energy of the incident photon determines the frequency, wavelength and colour of light emitted by the atom.

The energy level to which an atom is excited is determined by the kinetic energy of the incident electron. As the voltage increases, the kinetic energy of the electron increases, the further the atom is from the source of free electrons, the greater the required kinetic energy of free electron. When electrons are excited to higher energy levels, they must return to ground state.

4 0

3 years ago

a ball thrown vertically downwatd stikes a horizontal surface with a speed of 15 meters per seconds if then bounces and reaches

Anna71 [15]

but why was it thrown is the real question

3 0

3 years ago

An 85.0 kg fisherman jumps from a dock at a speed of 4.30 m/s onto their 135.0 kg boat. If the boat was at rest to begin but mov

jeka94

Answer:

Final speed of boat + man is 1.66 m/s

Explanation:

As we know that there is no friction on the system or there is no external force on this system

So here we can use momentum conservation here

$mv = (m + M)v_f$

so we have

m = 85 kg

M = 135 kg

v = 4.30 m/s

now we have

$85 \times 4.30 = (85 + 135) v$

$v = 1.66 m/s$

4 0

3 years ago

A 0.6 kg block attached to a spring of force constant 13.6 N/m oscillates with an amplitude of 9 cm. Find the maximum speed of t

mash [69]

Answer:

1) 0.43 meters per second

2) 0.21 meters per second

3) 1.02 $\frac{m}{s^{2}}$

4) 0.66 seconds

Explanation:

part 1

By conservation of energy, the maximum kinetic energy (K) of the block is at equilibrium point where the potential energy is zero. So, at the equilibrium kinetic energy is equal to maximum potential energy (U):

$K=U$

$\frac{mv^2}{2}=\frac{kx_{max}^2}{2}$

With m the mass, v the speed, k the spring constant and xmax the maximum position respect equilibrium position. Solving for v

$v=\sqrt{\frac{kx_{max}^2}{m}}=\sqrt{\frac{(13.6)(0.09m)^2}{0.6}}=0.43\frac{m}{s}$

part 2

Again by conservation of energy we have kinetic energy equal potential energy:

$\frac{mv^2}{2}=\frac{kx_{max}^2}{2}=$

$v=\sqrt{\frac{kx_{max}^2}{m}}=\sqrt{\frac{(13.6)(0.045m)^2}{0.6}}=0.21\frac{m}{s}$

part 3

Acceleration can be find using Newton's second law:

$F=ma$

with F the force, m the mass and a the acceleration, but elastic force is -kx, so:

$-kx=ma$

$a= -\frac{kx}{m}=-\frac{(13.6)(0.045)}{0.6}=-1.02\frac{m}{s^{2}}$

part 4

The period of an oscillator is the time it takes going from one extreme to the other one, that is going form 4.5 cm to -4.5 cm respect the equilibrium position. That period is:

$T=2\pi\sqrt{\frac{m}{k}}=T=2\pi\sqrt{\frac{0.6}{13.6}}=1.32s$

So between 0 and 4.5 cm we have half a period:

$t=\frac{T}{2}=0.66s$

7 0

3 years ago

Un automóvil se mueve 80 m en 40 s con una velocidad constante. ¿Cuál es la velocidad del automóvil? Ayuda plissssssssssssssssss

Alexxandr [17]

Answer:

Velocidad = 2 m/s

Explanation:

Dados los siguientes datos;

Distancia = 80 m

Tiempo = 40 s

Para encontrar la velocidad del automóvil;

La velocidad se puede definir como la tasa de cambio en el desplazamiento (distancia) con el tiempo.

La velocidad es una cantidad vectorial y, como tal, tiene magnitud y dirección.

Matemáticamente, la velocidad viene dada por la ecuación;

$Velocidad = \frac {distancia} {tiempo}$

Sustituyendo en la fórmula, tenemos;

Velocidad = 80/40

Velocidad = 2 m/s

5 0

3 years ago