All categories

2 years ago

Ask Questions Action and reaction force pairs are all around you, but they aren't always obvious. Write down

Physics

1 answer:

NARA [144]2 years ago

5 0

Answer:

Writing with a pencil. The pencil pushes on the paper. The paper pushes on the pencil.

Explanation:

Newton's third law.

You might be interested in

A pebble is dropped from rest from the top of a tall cliff and falls 53.4 m after 3.3 s has elapsed. How much farther does it dr

jeka94

Answer:

426.84 m

Explanation:

initial velocity u = 0

time t = 3.3 s

distance travelled s = 53.4 m

acceleration due to gravity = g

s = ut + 1/2 g t²

53.4 = 0 + 1/2 g x 3.3²

g = 9.8 m /s²

For the whole length of fall

distance travelled = h

total time = 6.6 + 3.3 = 9.9 s

h = ut + 1/2 g t²

u again = 0

h = .5 x 9.8 x 9.9²

= 480.24 m

distance travelled in last 6.6 s

= 480.24 - 53.4

= 426.84 m

6 0

2 years ago

The Burj Khalifa in Dubai is the world's tallest building. The structure is 828 m (2,716.5 feet) and has more than 160 stories.

Elena L [17]

Answer:

h = 599.5 m

Explanation:

Given,

height of structure = 828 m

weight of the tourist = 184 lb

= 184 x 0.45359 = 83.43 Kg

Potential energy = 187000 J

PE = m gd

$d = \frac{PE}{mg}$

$d = \frac{187000}{83.43\times 9.81}$

h = 228.5 m

Height of the room above the ground.

h = 828 - 228.5

h = 599.5 m

Height of the floor above ground is equal to 599.5 m.

4 0

3 years ago

Assuming that Albertine's mass is 60.0 kg , for what value of μk, the coefficient of kinetic friction between the chair and the

makvit [3.9K]

Answer:

$\mu_k=0.101$

Explanation:

It is given that,

Mass of Albertine, m = 60 kg

It can be assumed, the spring constant of the spring, k = 95 N/m

Compression in the spring, x = 5 m

A glass sits 19.8 m from her outstretched foot, h = 19.8 m

When she just reach the glass without knocking it over, a force of friction will also act on it. Using the conservation of energy for the spring mass system such that,

$\dfrac{1}{2}kx^2=\mu_k mgh$

$\mu_k=\dfrac{kx^2}{2mgh}$

$\mu_k=\dfrac{95\times (5)^2}{2\times 60\times 9.8\times 19.8}$

$\mu_k=0.101$

So, the coefficient of kinetic friction between the chair and the waxed floor is 0.101. Hence, this is the required solution.

3 0

3 years ago

Does a feather fall as fast as a rock in a vacuum? If so why?

7nadin3 [17]

Answer:

No.

Explanation:

A feather is less dense and thus less force exerted while a rock is very dense thus exerting more force .

3 0

3 years ago

A(n) 0.49 kg softball is pitched at a speed of 13 m/s. The batter hits it back directly at the pitcher at a speed of 23 m/s. The

garik1379 [7]

<h2>Impulse = 4.9 kgm/s</h2>

Explanation:

Impulse is given by change of momentum.

Mass of softball = 0.49 kg

Initial velocity of softball = 13 m/s

Initial momentum = 0.49 x 13 = 6.37 kgm/s

Final velocity of softball = 23 m/s

Final momentum = 0.49 x 23 = 11.27 kgm/s

Change of momentum = Final momentum - Initial momentum

Change of momentum = 11.27 - 6.37

Change of momentum = 4.9 kgm/s

Impulse = Change of momentum

Impulse = 4.9 kgm/s

4 0

3 years ago