Can someone please answer this, ill give you brainliest and your getting 100 points.
2 answers:
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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.
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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Part of the question is missing. Here it is:
<em>A 72 g autographed baseball slides off of a 1.3 m high table and strikes the floor a horizontal distance of 0.7m away from the table. The acceleration of gravity is 9.81 m/s2. What was the direction of the ball’s velocity just before it hit the floor? </em>
Answer:
Explanation:
The motion of the ball is a projectile motion, which consists of two separate motions:
- A horizontal motion at constant velocity
- A vertical motion at constant acceleration (free fall)
We start by analyzing the vertical motion, to find the time of flight of the ball. This can be done by using the suvat equation
where, choosing downward as positive direction:
s =1.3 m is the vertical displacement of the ball
u = 0 is the initial vertical velocity
is the acceleration of gravity
t is the time
Solving for t,
Now we can find the final vertical velocity of the ball, using:
And susbtituting t = 0.52 s, we find
It is important to keep in mind that the direction of this velocity is downward, since we chose downward as positive direction.
The horizontal velocity of the ball instead is constant; we know that the ball covers a horizontal distance of
d = 0.7 m
In a time of
t = 0.52 s
So, the horizontal velocity is
So now we can find the direction of the ball's velocity using:
And since the vertical direction is downward, this means that this velocity is below the horizontal, so the answer is