Answer:
when the ball is at rest in his coach's hands.
Explanation:
The forces on the basketball are balanced when the basketball is not experiencing any acceleration. This happens when the ball is in his coach's hand: in fact, at that moment the ball is at rest, so it means that its acceleration is zero. According to Newton's second law, this also mean that the net force on the basketball is zero, so the forces on the ball are balanced:
where F is the net force, m is the mass of the ball and a is the acceleration.
First of all, let's write the equation of motions on both horizontal (x) and vertical (y) axis. It's a uniform motion on the x-axis, with constant speed
, and an accelerated motion on the y-axis, with initial speed
and acceleration
:
where the negative sign in front of g means the acceleration points towards negative direction of y-axis (downward).
To find the distance from the landing point, we should find first the time at which the projectile hits the ground. This can be found by requiring
Therefore:
which has two solutions:
is the time of the beginning of the motion,
is the time at which the projectile hits the ground.
Now, we can find the distance covered on the horizontal axis during this time, and this is the distance from launching to landing point:
Hello there, the correct answer is:
B.
"Twice each second" means "2 per second". <em>Frequency = 2 Hz.</em>
<em>Period </em>= time for one bounce = <em>1 second</em>
Amplitude = distance between "not stretched" and "greatest stretch".
<em>Amplitude = 10 centimeters</em>
