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2 years ago

In 1929 Edwin Hubble used a telescope to discover the movement of galaxies. True or false

Physics

2 answers:

Zigmanuir [339]2 years ago

8 0

this statement is true Edwin Hubble did discover the movement of Galaxies

larisa86 [58]2 years ago

4 0

Explanation :

Edwin Hubble used a telescope to discover the movement of galaxies in 1929. He was an American Astronomer.

The telescope invented by him is called a Hubble telescope. It has a 2.4-meter mirror.

He gives the relation between the distance to a galaxy and its recessional velocity. This is known as the Hubble law. The relation is as follows :

$v=H_0\ r$

where,

$v$ is recessional velocity.

$H_0$ is Hubble constant.

$r$ is distance.

So, the given statement is True.

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A physics student throws a softball straight up into the air. The ball was in the air for a total of 3.56 s before it was caught

meriva

Answer:

The initial velocity of the softball is 14.711 meters per second.

Explanation:

This is a case of an object which experiments a free fall, that is, an uniform accelerated motion due to gravity and in which effects from air friction and Earth's rotation can be neglected.

From statement we must understand that the student threw the softball upwards and it is caught at original position 3.56 seconds later. Initial and final heights, time and gravitational acceleration are known and initial speed is unknown. The following equation of motion is used:

$y = y_{o} + v_{o}\cdot t + \frac{1}{2}\cdot g \cdot t^{2}$ (Eq. 1)

Where:

$y_{o}$ - Initial height of the softball, measured in meters.

$y$ - Final height of the softball, measured in meters.

$v_{o}$ - Initial velocity of the softball, measured in meters per second.

$t$ - Time, measured in seconds.

$g$ - Gravitational acceleration, measured in meters per square second.

If we know that $y = y_{o}$ , $t = 3.56\,s$ and $g = -9.807\,\frac{m}{s^{2}}$ , the initial velocity of the softball is:

$v_{o}\cdot (3\,s)+\frac{1}{2}\cdot (-9.807\,\frac{m}{s^{2}} )\cdot (3\,s)^{2} = 0$

$3\cdot v_{o} -44.132\,m= 0$

$v_{o} = 14.711\,\frac{m}{s}$

The initial velocity of the softball is 14.711 meters per second.

8 0

3 years ago

Liam throws a water balloon horizontally at 8.2 m/s out of a window 18 m from the ground.

Alecsey [184]

Time taken by the water balloon to reach the bottom will be given as

$h = \frac{1}{2} gt^2$

here we know that

$h = 18 m$

$g = 9.8 m/s^2$

now by the above formula

$18 = \frac{1}{2}*9.8* t^2$

$18 = 4.9 t^2$

$t = 1.92 s$

now in the same time interval we can say the distance moved by it will be

$d = v_x * t$

$d = 8.2 * 1.92 = 15.7 m$

so it will fall at a distance 15.7 m from its initial position

5 0

3 years ago

A 300 kg car initially travels with a velocity of 20 m/s to the right. A net force F acts on the car for 5 s, which causes the v

hram777 [196]

Answer:

600N.

Explanation:

From the question, we are to calculate the net force acting on the car.

According to Newton's second law of motion:

F = ma

m is the mass of the car

a is the acceleration = change in velocity/Time

a = v-u/t

F = m(v-u)/t

v is the final velocity = 30m/s

u is the initial velocity = 20m/s

t is the time = 5secs

m = 300kg

Get the net force:

Recall that: F = m(v-u)/t

F = 300(30-20)/5

F = 60(30-20)

F = 60(10)

F = 600N

Hence the net force acting on the car is 600N.

3 0

3 years ago

A 2.00 kg box slides on a rough, horizontal surface, hits a spring with a speed of 1.90 m/s and compresses it a distance of 10.0

oksian1 [2.3K]

Answer:

Explanation:

Given

mass of box $m=2\ kg$

speed of box $v=1.9\ m/s$

distance moved by the box $x=10\ cm$

coefficient of kinetic friction $\mu _k=0.66$

Friction force $f_r=\mu_kN$

$f_r=0.66\times mg$

$f_r=0.66\times 2\times 9.8=12.936 \N$

Kinetic Energy of box will be utilize to overcome friction and rest is stored in spring in the form of elastic potential energy

$\frac{1}{2}mv^2=f_r\cdot x+\frac{1}{2}kx^2$

$\frac{1}{2}\times 2\times 1.9^2=12.936\times 0.1+\frac{1}{2}\times k\times (0.1)^2$

$3.61-1.2936=0.005\times k$

$k=463.28\ N/m$

3 0

2 years ago

Read 2 more answers

A ball is released from the top of a tower of height h meters. it takes T seconds to reach the ground . what is the position of

alekssr [168]

Answer:the

8/9 h

Explanation:

Height = 1/2 a T^2 now change to T/3

now height = 1/2 a (T/3)^2 = 1/9 1/2 a T^2 <===== it is 1/9 of the way down or 8/9 h

3 0

1 year ago