A tennis ball is thrown vertically upward wih an initial velocity of 8.0m/s.

A) What will its speed be wheen it returns to its tarting point?
B) How long will it take for it to reach its starting poing?

(A)Speed = 8m/s

(B)u=8m/s
v=0m/s
a=g=9.8m/s2
Use
v=u-gt
0=8-9.8t
9.8t=8
t=8/9.8
But this is the time required by the tennis ball to reach the highest point.
Time taken by the ball to return to the starting point=2t
=2*8/9.8
=8/4.9
=1.632s

A volleyball is thrown vertically upward with an initial velocity of 7.5 m/s.

A.What will its speed be when it return to ita starting point?
B.How long will it take for it to reach its maximum height?

Let's solve the problems step by step:

A) What will its speed be when it returns to its starting point?

When the tennis ball reaches its starting point again, its speed will be equal to its initial velocity, but in the opposite direction.

Since the ball was thrown vertically upward, it will reach its highest point and start falling back downwards. At its highest point, its velocity will be zero.

To find the final velocity (speed when it returns to its starting point), we can use the kinematic equation:

v² = u² + 2as

where:
v = final velocity
u = initial velocity
a = acceleration
s = displacement

Let's plug in the known values:
u = 8.0 m/s
v = ?
a = acceleration due to gravity (approximately 9.8 m/s², pointing downward)
s = 0 (since the displacement is zero when the ball returns to its starting point)

v² = u² + 2as
v² = (8.0 m/s)² + 2(-9.8 m/s²)(0)

v² = 64.0 m²/s²

Taking the square root of both sides, we find:

v ≈ ±8.0 m/s

Therefore, the speed of the ball when it returns to its starting point will be 8.0 m/s, but in the opposite direction.

B) How long will it take for it to reach its starting point?

To find the time it takes for the ball to reach its starting point, we can use the kinematic equation:

v = u + at

where:
v = final velocity (which is 0 m/s when the ball reaches its starting point)
u = initial velocity (8.0 m/s)
a = acceleration due to gravity (-9.8 m/s²)
t = time

0 = 8.0 m/s + (-9.8 m/s²)t

-8.0 m/s = -9.8 m/s²t

Dividing both sides by -9.8 m/s²:

t ≈ 0.82 seconds

Therefore, it will take approximately 0.82 seconds for the tennis ball to reach its starting point.

To answer both questions, we need to understand the basic principles of motion and apply the laws of physics. In this case, we will use the equations of motion to find the solution.

Let's break down the problem step by step:

A) What will its speed be when it returns to its starting point?
When the tennis ball is thrown upwards, it will eventually reach its highest point and start falling back towards its starting point. At the highest point, the ball's velocity will be zero. As it falls back, its velocity will increase due to the acceleration of gravity.

To calculate its speed when it returns to the starting point, we need to find the velocity at the highest point first.

We can use the equation of motion:
v = u + at
where:
v = final velocity
u = initial velocity
a = acceleration (in this case, acceleration due to gravity)
t = time

At the highest point, the velocity is zero. Therefore, we have:
0 = 8.0 m/s + (-9.8 m/s^2) * t

Solving for time (t):
-8.0 m/s = -9.8 m/s^2 * t
t = -8.0 m/s / -9.8 m/s^2
t ≈ 0.82 seconds

Now, we know that it takes approximately 0.82 seconds to reach the highest point. To find the total time for the ball to return to its starting point, we need to multiply this time by 2, as it takes the same amount of time to go up and come down.

Total time = 0.82 seconds * 2 = 1.64 seconds

Therefore, it will take approximately 1.64 seconds for the tennis ball to return to its starting point.

B) How long will it take for it to reach its starting point?
Since we have already found the time it takes for the ball to reach the highest point (0.82 seconds), and we know that it takes the same amount of time to reach the starting point from the highest point, the answer is 0.82 seconds.

To summarize:
A) The speed of the tennis ball when it returns to its starting point is the same as its initial velocity, which is 8.0 m/s.
B) It takes approximately 0.82 seconds for the tennis ball to reach its starting point.