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3 years ago

What is meant by radioactivity?

Physics

1 answer:

vladimir1956 [14]3 years ago

4 0

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

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Two students race up a flight of steps together. "Student A" reaches the top of the steps 2 seconds ahead of

oksano4ka [1.4K]

Um student a because they were there a few seconds ahead

3 0

3 years ago

Find the equivalent resistance of this

frosja888 [35]

Answer:

Re=160ohm

Explanation:

Step#1

Rt=R1+R2 ( because both are in series)

Rt=(100+220 ) ohm

Rt=320 ohm

Step#2

Rt and R3 are parallel so,

Re= (Rt× R3) ÷ (Rt+R3)

Re= (320×320)÷( 320+320)

Re = 102,400÷ 640

Re=160ohm

7 0

3 years ago

A boy on a skateboard is pushed down the sidewalk by a friend. The skateboard rolls for a while but eventually comes to a stop.

Ket [755]

Friction is causing the skateboard to stop rolling.

4 0

3 years ago

Read 2 more answers

A 40 kg girl and an 8.4 kg sled are on the surface of a frozen lake, 15 m apart. By means of a rope, the girl exerts a 5.2 N for

stealth61 [152]

Answer:

(a) $a_s=0.62\frac{m}{s^2}$

(b) $a_s=0.13\frac{m}{s^2}$

Explanation:

(a) According to Newton's second law, the acceleration of a body is directly proportional to the force exerted on it and inversely proportional to it's mass.

$a_s=\frac{F}{m_s}\\a_s=\frac{5.2N}{8.4kg}\\a_s=0.62\frac{m}{s^2}$

(b) According to Newton's third law, the force that the sled exerts on the girl is equal in magnitude but opposite in the direction of the force that the girl exerts on the sled:

$a_g=\frac{F}{m_g}\\a_g=\frac{5.2N}{40kg}\\a_g=0.13\frac{m}{s^2}$

$x_f=x_0+v_0t \pm \frac{at^2}{2}$

For the girl, we have $x_0=0$ and $v_0=0$ . So:

$x_f_g=\frac{a_gt^2}{2}(1)$

For the sled, we have $v_0=0$ . So:

$x_f_s=x_0_s-\frac{a_st^2}{2}(2)$

When they meet, the final positions are the same. So, equaling (1) and (2) and solving for t:

$x_0_s-\frac{a_st^2}{2}=\frac{a_st^2}{2}\\t^2(a_g+a_s)=2x_0_s\\t=\sqrt{\frac{2x_s_0}{a_g+a_s}}\\t=\sqrt{\frac{2(15m)}{0.13\frac{m}{s^2}+0.62\frac{m}{s^2}}}\\t=6.32s$

Now, we solve (1) for $x_f_g$

$x_f_g=\frac{0.13\frac{m}{s^2}(6.32s)^2}{2}\\x_f_g=2.6m\\x_f=2.6m$

5 0

3 years ago

Social problems obstruct the development of society

aniked [119]

Answer:

This leads to backwardness and lagging in the development of the the society. Social problems such as sickness, poverty , social injustices , corruption , nepotism, tribalism are slowing down the process of development .

8 0

3 years ago