Answer:
It would take the object 5.4 s to reach the ground.
Explanation:
Hi there!
The equation of the height of a free-falling object at any given time, neglecting air resistance, is the following:
h = h0 + v0 · t + 1/2 · g · t²
Where:
h = height of the object at time t.
h0 = initial height.
v0 = initial velocity.
g = acceleration due to gravity (-32.2 ft/s² considering the upward direction as positive).
t = time
Let´s supose that the object is dropped and not thrown so that v0 = 0. Then:
h = h0 + 1/2 · g · t²
We have to find the time at which h = 0:
0 = 470 ft - 1/2 · 32.2 ft/s² · t²
Solving for t:
-470 ft = -16.1 ft/s² · t²
-470 ft / -16.1 ft/s² = t²
t = 5.4 s
Answer:
B) 3.50 m/s
Explanation:
The linear velocity in a circular motion is defined as:
The angular frequency (
) is defined as 2π times the frequency and r is the radius, that is, the distance from the center of the circular motion.
Replacing (2) in (1):
We have to convert the frequency to Hz:
Finally, we calculate how fast is the child moving:
Answer:
Explanation:
If a baseball is hit into the air with a velocity of 27 m/s, we want to determine the maximum height of the ball. Using the projecile formula;
Max height H = u²/2g
u is the initial velocity of the body = 27m/s
g is the acceleration due to gravity = 9.81m/s²
H = 27²/2(9.81)
H = 729/19.62
H = 37.16m
Hence the ball went 37.16m high
Answer:
The answer is C.
Explanation:
Let's take a glass of water as an example. Now, shine a flashlight on it. See it bend the light into a rainbow? That is a example of refraction. When the light enters the water, the water actually slows down and changes its direction, causing the light to come out the other side in a different way. Since water is very dense, it can bend the water and make it different.
