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3 years ago

What are not examples of velocity

Physics

2 answers:

Nookie1986 [14]3 years ago

8 0

Answer:

Explanation:

Acceleration roughly means “change in velocity.” If this change in velocity is consistently in one direction, the body will reach a point at which its velocity is zero.

Another consideration is when you drop a basketball onto the pavement. The ball falls, hits the ground, and comes back up. Because its direction of motion changed, you know that its velocity MUST have been 0 m/s at some point during the bounce.

This doesn't mean there was no acceleration at this point.

maw [93]3 years ago

4 0

How long it takes to get somewhere

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Using the law of conservation of angular momentum, estimate how fast a collapsed stellar core would spin if its initial spin rat

Nataly_w [17]

Answer:

$\omega_{f} = 1000000\,\frac{rev}{day}$

Explanation:

The law of conservation of angular momentum states that angular momentum remains constant when there is no external moment or forces applied to the system. Let assume that star can be modelled as an sphere, then:

$\frac{2}{5}\cdot M\cdot R_{o}^{2} \cdot \omega_{o} = \frac{2}{5}\cdot M\cdot R_{f}^{2} \cdot \omega_{f}$

The final angular speed is:

$\omega_{f} = \omega_{o}\cdot (\frac{R_{o}}{R_{f}})^{2}$

$\omega_{f} = (1\,\frac{rev}{day} )\cdot (\frac{10000\,km}{10\,km} )^{2}$

$\omega_{f} = 1000000\,\frac{rev}{day}$

3 0

2 years ago

What was the first manmade satellite put into orbit

Nataly_w [17]

The Soviet Union's Sputnik 1, it was launched October 4th 1957.

5 0

3 years ago

In a common but dangerous prank, a chair is pulled away as a person is moving downward to sit on it, causing the victim to land

Marina CMI [18]

Answer:

(a) $\vec{J}=176.4\frac{kg*m}{s} \hat{j}$

(b) $F=2125.30N$

Explanation:

(a) According to the law of conservation of energy, the potential energy of the person at 0.40 m is equal to its kinetic energy before the colision with the floor:

$\Delta U=\Delta K\\mgh=\frac{mv^2}{2}\\v=\sqrt{2gh}\\v=\sqrt{2(9.8\frac{m}{s^2})(0.40m)}\\v=2.8\frac{m}{s}$

This is the initial velocity in the negative y-direction. Impulse is given by:

$\vec{J}=\Delta \vec{p}\\\vec{J}=m\vec{v_f}-m\vec{v_i}\\\vec{J}=63kg(0 \hat{j})-63kg(-2.8\frac{m}{s} \hat{j})\\\vec{J}=176.4\frac{kg*m}{s} \hat{j}$

(b) The average force is:

$F=\frac{J}{\Delta t}\\F=\frac{176.4\frac{kg*m}{s}}{0.083s}\\F=2125.30N$

6 0

3 years ago

ad for the distance from the sun tothe earth is 1.5 x 10"m. how long does it take for light from ths sun to reach the eath? give

Alexandra [31]

Answer:

About 8.3 minutes

Explanation:

Use the formula for velocity as the distance covered by the light divided the time it takes: $[tex]velocity=\frac{distance}{time}$ [/tex]

Use the information about the speed of light in vacuum: $300000000 \frac{m}{s} = 3*10^{8} \frac{m}{s}$

and the information you are given regarding the distance between Sun and Earth: $1.5 * 10^{11} m$

to solve the first velocity equation for the unknown time "t":

$velocity=\frac{distance}{time} \\3*10^8\frac{m}{s} =\frac{1.5*10^11 m}{t} \\t=\frac{1.5*10^11 }{3*10^8} s= 500 s$

we can convert second into minutes by dividing by 60: 500 s = 500/60 minutes = 8.3333... minutes

5 0

3 years ago

An old movie poster used a quote "in space no one can hear you scream!"which of these best explains this quote

soldi70 [24.7K]

I think the complete question is:

An old movie poster used a quote "In space, no one can hear you scream!" Which of these best explains the quote?

A) The quote is incorrect, you can hear sound in outer space.

B) Sound cannot be polarized. So, you cannot hear sound in space.

C) Sound is an electromagnetic wave and needs no medium to travel through.

D) Sound needs a medium for the wave to vibrate and there is nothing in space to vibrate.

Answer:

D) Sound needs a medium for the wave to vibrate and there is nothing in space to vibrate.

Explanation:

There are two types of waves:

Mechanical Waves : These waves requires are medium to travel from one point of space to another point of space. Sound wave is one such example. Since they depend upon medium so speed of travelling also depend upon medium.
Electromagnetic Waves : These type of waves do not require a medium to travel. If medium exists then it will cause some hindrance in there path but still they will travel. For example: Light waves, X-Rays, Microwaves, Infrared waves, Ultraviolet waves etc.

In space no particle exists so no mechanical waves, such as sound, can travel through it but any electromagnetic wave can travel, such as light. That is why when astronauts are in space walk or when they are in outer space then they do not talk rather they use sign language to communicate

4 0

3 years ago

Read 2 more answers