A billiard ball collides with a stationary identical billiard ball to make it move. If the collision is perfectly elastic, the first ball comes to rest after collision.
<h3>Why does the first ball comes to rest after collision ?</h3>
Let m be the mass of the two identical balls.
u1 = velocity before the collision of ball 1
u2 = 0 = velocity of second ball that is at rest
v1 and v2 are the velocities of the balls after the collision.
From the conservation of momentum,
∴ mu1 + mu2 = mv1 + mv2
∴ mu1 = mv1 + mv2
∴ u1 = v1 + v2
In an elastic collision, the kinetic energy of the system before and after collision remains same.

∴ 
∴ 
∴
₁
₂ = 0
- It is impossible for the mass to be zero.
- Because the second ball moves, velocity v2 cannot be zero.
- As a result, the velocity of the first ball, v1, is zero, indicating that it comes to rest after collision.
<h3>What is collision ?</h3>
An elastic collision is a collision between two bodies in which the total kinetic energy of the two bodies remains constant. There is no net transfer of kinetic energy into other forms such as heat, noise, or potential energy in an ideal, fully elastic collision.
Can learn more about elastic collision from brainly.com/question/12644900
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Answer:
- 0.09 % of the original radioactive nucllde its left after 10 half-lives
- It will take 241,100 years for 10 half-lives of plutonium-239 to pass.
Explanation:
The equation for radioactive decay its:
,
where N(t) its quantity of material at time t,
its the initial quantity of material and
its the mean lifetime of the radioactive element.
The half-life
its the time at which the quantity of material its the half of the initial value, so, we can find:

so:




So, after 10 half-lives, we got:




So, we got that a 0.09 % of the original radioactive nucllde its left.
Putonioum-239 has a half-life of 24,110 years. So, 10 half-life will take to pass

It will take 241,100 years for 10 half-lives of plutonium-239 to pass.
Answer:
The time for final 15 cm of the jump equals 0.1423 seconds.
Explanation:
The initial velocity required by the basketball player to be able to jump 76 cm can be found using the third equation of kinematics as

where
'v' is the final velocity of the player
'u' is the initial velocity of the player
'a' is acceleration due to gravity
's' is the height the player jumps
Since the final velocity at the maximum height should be 0 thus applying the values in the above equation we get

Now the veocity of the palyer after he cover'sthe initial 61 cm of his journey can be similarly found as

Thus the time for the final 15 cm of the jump can be found by the first equation of kinematics as

where symbols have the usual meaning
Applying the given values we get

Answer:
Electric Field intensity is zero.
The reason for that is:
All charges are placed at equal distances from the center of the square and have same magnitude and sign. This means they will exert equal and opposite forces on the test charge at the center. Net force will become Zero.
Secondary succession, the more common type of succession, occurs on a surface where an ecosystem has previously existed. It occurs in ecosystems that have been disturbed or disrupted by humans, animals, or by natural processes such as storms, floods, earthquakes, and volcanoes.