If two people hit identical tennis balls at the same time, the ball that has the most kinetic energy is the ball that moves at the fastest speed.
<u>Explanation:</u>
The energy possessed by an object by virtue of its motion is called its kinetic energy indicating that only moving objects have kinetic energy. The kinetic energy of an object depends on its speed and mass.
It is given by the expression

where m denotes the mass of the object and v denotes its velocity.
since kinetic energy is directly proportional to the square of the velocity, the kinetic energy of an object increases with its velocity.
Hence an object that moves at the fastest speed will have the most kinetic energy.
We can calculate his resultant speed.
Resultant speed is:
v^2 = 5^2 + 1,9^2
v = 5,349 m/s
Now we need to find angle between resultant speed and vertical speed.
cos(alpha) = 5/5.349 = 0.9347
alpha = 20,8 degrees
Answer is 20,8 degrees
Answer: K =24 psi
Explanation:
Given: Standard deviation =3psi
Internal pressure strength =157psi
Number of random bottle =n=64
K= 3 × square root of 64
K= 3×8=24 psi
If mean internal pressure K fall below K,
157-1.3=155.7psi
At 2%:
0.16×64 = 10.24