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3 years ago

20-kilogram canoe is floating downriver at 2 m/s. what’s the kinetic energy?

Physics

2 answers:

ziro4ka [17]3 years ago

6 0

Answer:

40J

Explanation:

Kinetic energy = 1/2 mv^2

Where m = mass and

v = velocity

Given mass = 20kg

v = 2m/s

K.E = 1/2 x 20 x2^2

= 1/2 x 20 x 2 x 2

= 80/2

= 40J

ryzh [129]3 years ago

3 0

To a physicist floating next to it in another canoe, its KE is zero.

To a physicist standing on the riverbank watching it go by, its KE is 40J.

They're both correct for their own reference frame.

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In my trigonometry class, we were assigned a problem on Angular and Linear Velocity.

Rzqust [24]

1) 0.0011 rad/s

2) 7667 m/s

Explanation:

The angular velocity of an object in circular motion is equal to the rate of change of its angular position. Mathematically:

$\omega=\frac{\theta}{t}$

where

$\theta$ is the angular displacement of the object

t is the time elapsed

$\omega$ is the angular velocity

In this problem, the Hubble telescope completes an entire orbit in 95 minutes. The angle covered in one entire orbit is

$\theta=2\pi$ rad

And the time taken is

$t=95 min \cdot 60 =5700 s$

Therefore, the angular velocity of the telescope is

$\omega=\frac{2\pi}{5700}=0.0011 rad/s$

For an object in circular motion, the relationship between angular velocity and linear velocity is given by the equation

$v=\omega r$

where

v is the linear velocity

$\omega$ is the angular velocity

r is the radius of the circular orbit

In this problem:

$\omega=0.0011 rad/s$ is the angular velocity of the Hubble telescope

The telescope is at an altitude of

h = 600 km

over the Earth's surface, which has a radius of

R = 6370 km

So the actual radius of the Hubble's orbit is

$r=R+h=6370+600=6970 km = 6.97\cdot 10^6 m$

Therefore, the linear velocity of the telescope is:

$v=\omega r=(0.0011)(6.97\cdot 10^6)=7667 m/s$

4 0

3 years ago

How many seconds will it take for a the International Space Station to travel 450 km at a rate of 100 m/s?

SVEN [57.7K]

Time = (distance) / (speed)

Time = (450 km) / (100 m/s)

Time = (450,000 m) / (100 m/s)

Time = <em>4500 seconds </em>(that's 75 minutes)

Note:

This is about HALF the speed of the passenger jet you fly in when you go to visit Grandma for Christmas.

If the International Space Station flew at this speed, it would immediately go ker-PLUNK into the ocean.

The speed of the International Space Station in its orbit is more like 3,100 m/s, not 100 m/s.

8 0

3 years ago

All ions are atoms with a

Cloud [144]

All ions are atoms with a charge

3 0

3 years ago

Help please this is important!

bixtya [17]

Answer:

Since the ball becomes positively charged, it will repel as like charges repel.

7 0

3 years ago

Lila is a track and field athlete. She must complete four laps around a circular track. The track itself is a 400 meter track an

Aleonysh [2.5K]

Answer:

Her speed is 1.1 m/s, and her velocity is 0 m/s

Explanation:

Speed = Distance covered/Time

Given

Distance = 400m

Time = 6minutes = 6*60 = 360 secs

Substitute the given parameter into the formula;

Speed = 400/360

Speed = 1.1m/s

Since the track is a circular track, the displacement will be zero. She is only moving in a circular path (no direction)

Velocity = Displacement/Time

Velocity = 0/3600

Velocity = 0m/s

Hence her speed is 1.1 m/s, and her velocity is 0 m/s

6 0

3 years ago