Which of the following best defines speed?

A goalie kicks a soccer ball straight vertically into the air. It takes 5.00 s for the ball to reach its maximum height and come

Yuliya22 [10]

Answer:

(a) vo = 24.98m/s

(b) t = 5.09 s

Explanation:

(a) In order to calculate the the initial speed of the ball, you use the following formula:

$y=y_o+v_ot-\frac{1}{2}gt^2$ (1)

y: vertical position of the ball = 2.44m

yo: initial vertical position = 0m

vo: initial speed of the ball = ?

g: gravitational acceleration = 9.8m/s²

t: time on which the ball is at 2.44m above the ground = 5.00s

You solve the equation (1) for vo and replace the values of the other parameters:

$v_o=\frac{y-y_o+1/2gt^2}{t}$

$v_o=\frac{2.44m-0.00m+1/2(9.8m/s^2)(5.00s)^2}{5.00s}\\\\v_o=24.98\frac{m}{s}$

The initial speed of the ball is 24.98m/s

(b) To find the time the ball takes to arrive to the ground you use the equation (1) for y = 0m (ground) and solve for t:

$0=24.98t-\frac{1}{2}(9.8)t^2\\\\t=5.09s$

The time that the ball takes to arrive to the ground is 5.09s

5 0

3 years ago

A mass of 2 kg is attached to a spring and placed on a horizontal surface. The spring has a spring constant of 20 N/m, and the s

Sergio [31]

The speed of the mass : <em><u>v = 0.316 m/s</u></em>

<h3>Further explanation</h3>

The energy used to press a spring is included as the potential energy

Can be formulated:

$\displaystyle E_p=\frac{1}{2}kx^2$

Ep= potential energy

k = spring constant

x = change in spring length

If the spring is released from its pressure, this potential energy will turn into kinetic energy

so applies the law of conservation of mechanical energy (Em)

Ek = Ep

A mass of 2 kg is attached to a spring, a spring constant of 20 N/m, and the spring is compressed 0.1 m past its natural length.

m = 2 kg

k = 20 N/m

x = 0.1 m

$\displaystyle Ep=Ek\\\\\frac{1}{2}kx^2=\frac{1}{2}mv^2\\\\kx^2=mv^2\\\\20\times0.1^2=2\times v^2\\\\v^2=0.1\\\\v=\sqrt{0.1}\\\\v=0.316~m/s$

<h3>Learn more</h3>

Hooke's law

brainly.com/question/2648431

Keywords : spring,mass, spring constant,compressed position

5 0

3 years ago

PLEASE HELP ME ASAP PLEASE PLEASE!!!!!

Effectus [21]

Answer:bottom left

Explanation:

8 0

3 years ago

Read 2 more answers

Oftentimes the president appears on television handing out awards to American citizens. Which of the president’s many roles BEST

9966 [12]

The correct answer would be a) head of state.

Chief executives carry out executive orders.
The commander in chief carries out military orders and commands military forces. Leaders of foreign policy deal enforce international policies.

3 0

4 years ago

A student plucks a fixed-end string, creating a standing wave with 6.00 nodes (including any nodes at the ends). The string is t

Vesna [10]

1) 2.5 wavelengths

2) 0.208 m

3) 1731 Hz

Explanation:

1)

Standing waves are waves that do not propagate, but instead the particles of the medium just oscillate around a fixed position. Examples of standing waves are the waves produced on a string with fixed ends.

The points of a standing wave in which the amplitude of the oscillation is always zero are called nodes.

The two fixed ends of the string are two nodes. In this problem, we have a total of 6 nodes along the string: this means that there are 4 additional nodes apart from the two ends of the string.

Therefore, this also means that the string oscillate in 5 different segments.

One wavelength is equal to 2 segments of the oscillation: therefore, since here there are 5 segments, this means that the number of wavelengths that we have in this string is

$n=\frac{5}{2}=2.5$

2)

The wavelength of a wave is the distance between two consecutive crests (or throughs) of the wave.

The wavelength of a standing wave can be also measured as the distance between the nth-node and the (n+2)-th node: so, basically, the wavelength in a standing wave is twice the distance between two nodes:

$\lambda = 2 d$