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katrin2010 [14]

3 years ago

9

A star has a spectrum with lines indicating the presence of ionized helium. This star should be classified as a(n) _____ type st

ar.
O
A
G
M

2 answers:

Oduvanchick [21]3 years ago

4 0

It should be o,not 100% sure tho

scoundrel [369]3 years ago

4 0

Answer:

A star has a spectrum with lines indicating the presence of ionized helium. This star should be classified as a(n) <u>O</u> type star.

Explanation:

Helium is a noble has. Its formation and ionization requires high temperature which is possible only in core of stars. Stars classified based on temperatures. Type O stars have very high temperatures (more than 30,000 K). At these temperatures, Helium gets ionized. Thus, the spectrum of O-type stars indicates the presence of ionized helium more than the neutral.

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A 98-kg fullback, running at 5.0 m/s, attempts to dive directly across the goal line for a touchdown. Just as he reaches the lin

Troyanec [42]

Answer:

(a) Explained below

(b) $v_f=0.35\ m/s$

(c) Yes

Explanation:

<u>Law Of Conservation Of Linear Momentum</u>

The total linear momentum of a system of particles or objects is conserved unless an external force is acting on the system. The formula for the momentum of a body with mass m and velocity v is P=mv. If there is a system of bodies, then the total linear momentum is the sum of the individual momentums

$P=m_1v_1+m_2v_2+...+m_nv_n$

When objects collide and join together, the only final mass is the sum of all masses, all traveling at the same speed.

Our $m_1=98\ kg$ fullback runs at $v_1=5\ m/s$ . Two two 68-kg linebackers attempt to stop him, one at -2.0 m/s and the other at -4.0 m/s. The negative value is because the run against the positive direction, taken in the direction of the fullback.

(a) Before the event, there is a total linear momentum, computed as the sum of the momentums of each player as shown

$p_1=m_1v_1=(98)(5)=490 Kg\ m/s$

$p_2=m_2v_2=(68)(-4)=-272 kg\ m/s$

$p_3=m_3v_3=(68)(-2)=-136 kg\ m/s$

$p_t=p_1+p_2+p_3=390-272-136=82\ kg\ m/s$

After the collision, all the players keep joined in one single mass of.

$m_t=98+68+68=234\ kg$

They will move at a speed which will be computed below

(b) The final momentum of the system is

$p_f=m_tv_f=82\ kg\ m/s$

Since the linear momentum is conserved, the final speed $v_f$ is common to all of the players. Let's solve to find it

$\displaystyle v_f=\frac{p_f}{m_t}$

$\displaystyle v_f=\frac{82}{234}$

$v_f=0.35\ m/s$

(c) Since the final speed of the players is positive, it means the touchdown was actually scored, the fullback moved forward across the goal line, the positive reference.

5 0

2 years ago

A rolling ball has an initial velocity of 1.6 meters per second. if the ball has a constant acceleration of 0.33 meters per seco

lukranit [14]

We have:

Initial velocity (u) = 1.6 m/s
Constant acceleration (a) = 0.33 m/s²
Time (t) = 3.6 sec

There are five constant acceleration equations that would help us to find the velocity:

$v=u+at$
$s=ut+ \frac{1}{2}at^2$
$s= \frac{1}{2}(u+v)t$
$v^2=u^2+2as$
$s=vt- \frac{1}{2}at^2$

Since we have $u, a, t$ and we want $v$
We will use the first formula $v=u+at$

$v=1.6+(0.33)(3.6)$
$v= 2.788$ m/s

7 0

2 years ago

What is the meaning of Choreography for Aerobic Dance?

MakcuM [25]

Aerobic dance<span> has its foundation in </span>dance<span>-inspired movements. It is a cardiovascular workout set to music in a group </span>exercise<span> setting. You do not have to memorize </span>dance<span> moves, as the classes are taught by instructors who verbally tell and visually show the </span>choreography<span>.</span>

4 0

2 years ago

What’s the answer to this

ladessa [460]

Choices 1, 2, and 4 . . . . . Yes

Choices 3 and 5 . . . . . No

6 0

3 years ago

You are tossing a ball directly up into the air. Before the ball leaves your hand, you are exerting a force directed against the

DaniilM [7]

Answer:

F n = 0.2 N

Explanation:

given,

you are exerting force of 10 N on the ball.

mass of the ball = 1 kg

acceleration due to gravity = 9.8 m/s²

normal force on the ball = ?

normal force is force exerted by the object to counteract the force from other object.

normal force acting on the ball will be

F n = F - mg

F n = 10 - 1 × 9.8

F n = 10 -9.8

F n = 0.2 N

Hence, normal force acting on the ball is equal to 0.2 N

7 0

3 years ago