Pls,help ASAP .the question is in attachment

What is meant by radioactivity?

vladimir1956 [14]

What that means is the atom is so radioactive that the nucleus is unstable.

4 0

3 years ago

A reconnaissance plane flies 605 km away from

kolezko [41]

Answer:

$v_{avg} =$ 355 m/s

Explanation:

Distance = 605 km

Initial speed = $v_{i}$ = 284 m/s

Final velocity = $v_{f}$ = 426 m/s

Average speed = ?

There is two method two find average speed. In first method, using 3rd equation of motion, we find acceleration.

$2as = v_{f}^{2}+v_{i}^{2}$

Then using first equation of motion, we find time

$v_{f} = v_{i}+at$

Then using the formula of average velocity, we find average velocity

$v_{avg}=\frac{total-distance}{total-time}$

Second method is very simple

$v_{avg}=\frac{v_{f}+v_{i} }{2}$

$v_{avg}=\frac{426+284}{2}$

$v_{avg} =$ 355 m/s

8 0

4 years ago

An object is located 70 cm from a concave mirror with a focal length of 15 cm. What is the image

Stels [109]

(a) The distance of the image formed by the concave mirror is 19.1 cm.

(b) The image formed is diminished and real.

<h3>Image distance </h3>

The distance of the image formed by the concave mirror is calculated as follows;

1/f = 1/v + 1/u

1/v = 1/f - 1/u

1/v = 1/15 - 1/70

1/v = 0.05238

v = 1/0.05238

v = 19.1 cm

The image distance is smaller than object distance, thus the image formed is diminished and real.

Learn more about concave mirror here: brainly.com/question/13164847

#SPJ1

5 0

2 years ago

An 100W light bulb is on 6 hours work out the energy (kWh) used and the cost of it (1kWh = £0.1359) with working out please

Ainat [17]

1,000 W = 1 kW
100 W = 0.1 kW

(0.1 kW) x (6 h) = 0.6 kWh <=== energy

(0.6 kWh) x (£0.1359/kWh) = £0.0815 <=== cost of it

8 0

3 years ago

By what factor must the amplitude of a sound wave be decreased in order to decrease the intensity by a factor of 3?

s344n2d4d5 [400]

Answer:

Amplitude is decreased by a factor of $\sqrt3$ if intensity is decreased by a factor of 3.

Explanation:

Intensity of a sound wave is directly proportional to the square of its amplitude.

Therefore, if intensity is $I$ and amplitude is $A$ , then

$I=kA^2$ , where, $k$ is constant of proportionality.

Now, if intensity of sound wave is decreased by a factor of 3. So,

New intensity is, $I_{new}=\frac{I}{3}$

$I_{new}=kA_{new}^2\\\frac{I}{3}=kA_{new}^2$

Plug in $kA^2$ for $I$ . This gives,

$\frac{kA^2}{3}=kA_{new}^2\\A_{new}^2=\frac{A^2}{3}\\A_{new}=\sqrt{\frac{A^2}{3}}=\frac{A}{\sqrt{3}}$

Therefore, amplitude is decreased by a factor of $\sqrt3$ .

4 0

3 years ago

Pls,help ASAP .the question is in attachment​

Pls,help ASAP .the question is in attachment