Ask question

Ask question

All categories

3 years ago

12

The star nearest to our Sun is called Proxima Centauri. It has a surface temperature of approximately 3000 Kelvin and a luminosi

ty about 1/1000th of the Sun’s. Which type of star is Proxima Centauri, and what color is it?

2 answers:

Mamont248 [21]3 years ago

4 0

Answer:

Proxima Centauri is a main sequence star, and it is red.

Explanation:

rusak2 [61]3 years ago

3 0

Ummmm is there any options?

You might be interested in

Two boxers are fighting. Boxer 1 throws his 5 kg fist at boxer 2 with a speed of 9 m/s.

Sladkaya [172]

Answer:

0.001 s

Explanation:

The force applied on an object is equal to the rate of change of momentum of the object:

$F=\frac{\Delta p}{\Delta t}$

where

F is the force applied

$\Delta p$ is the change in momentum

$\Delta t$ is the time interval

The change in momentum can be written as

$\Delta p=m(v-u)$

where

m is the mass

v is the final velocity

u is the initial velocity

So the original equation can be written as

$F=\frac{m(v-u)}{\Delta t}$

In this problem:

m = 5 kg is the mass of the fist

u = 9 m/s is the initial velocity

v = 0 is the final velocity

F = -45,000 N is the force applied (negative because its direction is opposite to the motion)

Therefore, we can re-arrange the equation to solve for the time:

$\Delta t=\frac{m(v-u)}{F}=\frac{(5)(0-9)}{-45,000}=0.001 s$

4 0

3 years ago

A science teacher tells her class that their final project requires students to measure a specific variable and determine the ve

iogann1982 [59]

Answer:

Yes

Explanation:

The velocity measured by Jennifer and Johnny is

$v_m = 34.87 m/s$

The actual velocity is

$v=34.15 m/s$

We can calculate the % error of the students measurement as follows:

$Err = \frac{v_m - v}{v}\cdot 100 = \frac{34.87 m/s-34.15 m/s}{34.15 m/s}\cdot 100 =0.021 \cdot 100 = 2.1 \%$

Which is lower than the 2.5% maximum error required, so the two students will pass the test.

4 0

3 years ago

A motor keep a Ferris wheel (with moment of inertia 6.97 × 107 kg · m2 ) rotating at 8.5 rev/hr. When the motor is turned off, t

Talja [164]

Answer:

$P = 133.13 Watt$

Explanation:

Initial angular speed of the ferris wheel is given as

$\omega_i = 2\pi f$

$\omega_i = 2\pi(8.5/3600)$

$\omega_i = 0.015 rad/s$

final angular speed after friction is given as

$\omega_f = 2\pi f$

$\omega_f = 2\pi(7.5/3600)$

$\omega_f = 0.013 rad/s$

now angular acceleration is given as

$\alpha = \frac{\omega_f - \omega_i}{\Delta t}$

$\alpha = \frac{0.015 - 0.013}{15}$

$\alpha = 1.27 \times 10^{-4} rad/s^2$

now torque due to friction on the wheel is given as

$\tau = I \alpha$

$\tau = (6.97 \times 10^7)(1.27 \times 10^{-4})$

$\tau = 8875.3 N m$

Now the power required to rotate it with initial given speed is

$P = \tau \omega$

$P = 8875.3 \times 0.015$

$P = 133.13 Watt$

8 0

3 years ago

How effectiveness of a small force is increased when action area of force is<br> reduced?

STatiana [176]

Answer:

The force is proportional to the area, for if we increase the area but keep the number of molecules per cubic centimeter the same, we increase the number of collisions with the piston in the same proportion as the area was increased.

Explanation:

more area =more space = more free for molecules = less pressure = less force.

3 0

3 years ago

What BAC is acceptable for teen drivers?

iragen [17]

If your talking about the blood alcohol content then there isn't a limit cause it would be underage drinking

7 0

3 years ago