A 60kg block rests on rough horizontal ground. A rope is

A planetâs moon revolves around the planet with a period of 39 Earth days in an approximately circular orbit of radius of 4.8Ã10

Alchen [17]

Answer:

v = 895 m/s

Explanation:

Time period is given as 39 Earth Days

$T = 39 days \times 24 hr \times 3600 s$

$T = 3369600 s$

now the radius of the orbit is given as

$r = 4.8 \times 10^8 m$

so the total path length is given as

$L = 2 \pi r$

$L = 2\pi (4.8 \times 10^8)$

$L = 3.015 \times 10^9$

now the speed will be given as

$v = \frac{L}{T}$

$v = \frac{3.015 \times 10^9}{3369600}$

$v = 895 m/s$

7 0

3 years ago

It was a dark and stormy night, when suddenly you saw a flash of lightning. Three-and-a-half seconds later you heard the thunder

Gekata [30.6K]

We're going to multiply the time it took for you to hear thunder (3.5 seconds) by the speed of sound in air (340 m/s)

3.5 x 340 = 1190

The lightning bolt was 1,190 meters away.

3 0

3 years ago

Como foi a despedida do bilhete?

Dmitrij [34]

Can you translate to english ?

8 0

3 years ago

A person throws a ball straight up. He releases the ball at a height of 1.75 m above the ground and with a velocity of 12.0 m/s.

Lyrx [107]

Answer:

a) 1.22 s

b) 9.089 m

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration due to gravity = 9.81 m/s²

$v=u+at\\\Rightarrow t=\frac{v-u}{a}\\\Rightarrow t=\frac{0-12}{-9.81}\\\Rightarrow t=1.22\ s$

Time taken by the ball to reach the highest point is 1.22 seconds

$s=ut+\frac{1}{2}at^2\\\Rightarrow s=12\times 1.22+\frac{1}{2}\times -9.81\times 1.22^2\\\Rightarrow s=7.339\ m$

The maximum height the ball will reach above the ground is 1.75+7.339 = 9.089 m

8 0

3 years ago

A heavy rope, 80 ft long and weighing 32 lbs, hangs over the edge of a building 100 ft high. how much work w is done in pulling

allochka39001 [22]

The first thing you should know for this case is that work is defined as the product of force by the distance traveled in the direction of force.
We have then:
W = Fd
The distance varies, so we must integrate:
from 0 to 20:
W = ∫F (x) dx
W = ∫32xdx
W = 32∫xdx
W = 32 (x ^ 2/2) = (16) (20 ^ 2) = 6400 ft * lbs
answer:
6400 ft * lbs is work done pulling the rope up 20 ft

6 0

3 years ago