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3 years ago

Why are some atoms radioactive

1 answer:

8 0

Atoms<span> are made of three types of sub-atomic particle: neutrons and protons in the nucleus and electrons orbiting the nucleus. </span>Some<span> materials are </span>radioactive<span> because the nucleus of each </span>atom<span> is unstable and gives out nuclear radiation in the form of alpha particles, beta particles or gamma rays.</span>

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What is the maximum speed (in units of m/s) with which a car can round a

IrinaK [193]

Answer:

B) 15.5 m/s

Explanation:

r = 60m

μs = 0.4

using the formula max V = √r*g*μs (flat roadway)

v = sqrt(60 * 10 * 0.4)

v = 15.5 m/s

5 0

3 years ago

In the water cycle ,matter moves towards of gravity during

Semenov [28]

In the water cycle, matter moves against the pull of gravity during infiltration and evaporation transpiration and infiltration precipitation and infiltration evaporation and transpiration

3 0

3 years ago

A billiard ball of mass 0.28 kg hits a second, identical ball at a speed of 7.2 m/s and comes to rest as the second ball flies o

Strike441 [17]

Answer:

(a) -8064 N

(b) 8064 N

Explanation:

(a)

From Newton’s law of motion, Force, F=ma where m is mass and a is acceleration.

Since acceleration is the rate of change of velocity per unit time, then where v is velocity and the subscripts f and I denote final and initial

For the first ball, the mass is 0.28 Kg, final velocity is zero since it finally comes to rest, t is 0.00025 s and initial velocity is given as 7.2 s. Substituting these values we obtain

$F=0.28\times \frac {0-7.2}{0.00025}=-8064 N$

(b)

For the second ball, the mass is also 0.28 Kg but its initial velocity is taken as zero, the final velocity of the second ball will be equal to the initial velocity of the second ball, that is 7.2 m/s and the time is also same, 0.00025 s. By substitution

$F=0.28\times \frac {7.2-0}{0.00025}=8064 N$

Here, we prove that action and reaction are equal and opposite

3 0

3 years ago

A type of anchor that is a good choice when jacking or leveling

Anika [276]

A type of anchor that is a good choice when jacking or leveling the fastening component is a stud bolt anchor.

<h3>What is a Stud bolt anchor?</h3>

These are the type of anchor which bare embedded in concrete with the threaded portion on the outside.

This makes it easier to jack or level the fastening component which is why option B was chosen.

Read more about Anchor here brainly.com/question/17187235

#SPJ1

4 0

2 years ago

A catapult launches a test rocket vertically upward from a well, giving the rocket an initial speed of 79.6 m/s at ground level.

Dimas [21]

Answer:

The rocket is motion above the ground for 44.7 s.

Explanation:

The equations for the height of the rocket are as follows:

y = y0 + v0 · t + 1/2 · a · t²

and, after the engine fails:

y = y0 + v0 · t + 1/2 · g · t²

Where:

y = height of the rocket at time t

y0 = initial height

v0 = initial speed

t= time

a = acceleration due to the engines

g = acceleration due to gravity

First, let´s calculate the time the rocket is being accelerated by the engines:

(The center of the framer of reference is located at the ground, y0 = 0).

y = y0 + v0 · t + 1/2 · a · t²

1190 m = 0 m + 79.6 m/s · t + 1/2 · 4.10 m/s² · t²

0 = 2.05 m/s² · t² + 79.6 m/s · t - 1190 m

Solving the quadratic equation:

t = 11.5 s (the other value of t is discarded because it is negative).

At that time, the engines fail and the rocket starts to fall. The equation of the height will be:

y = y0 + v0 · t + 1/2 · g · t²

The initial velocity (v0) will be the velocity acquired during 11.5 s of acceleration plus the initial velocity of launch:

v = v0 + a · t

v = 79.6 m/s + 4.10 m/s² · 11.5 s

v = 126.8 m/s

Now, we can calculate the time it takes the rocket to reach the ground (y = 0) from a height of 1190 m:

y = y0 + v0 · t + 1/2 · g · t²

0 m = 1190 m + 126.8 m/s · t - 1/2 · 9.80 m/s² · t²

Solving the quadratic equation:

t = 33.2 s

Then, the total time the rocket is in motion is (33.2 s + 11.5 s) 44.7 s

5 0

3 years ago