All categories

3 years ago

A rock is thrown across a frozen pond with an initial speed of 8m/s. Which statement best describes the motion of the rock?

Physics

1 answer:

olga55 [171]3 years ago

7 0

Answer:

Option C: "The rock will slow down and eventually stop"

Explanation:

Since this is a real event, and not an ideal situation where there is no friction forces acting between the frozen pond and the rock, there is going to exist some force of dynamic friction (even small) acting between them. One can look up coefficients of dynamic friction between similar objects, and realize that some small force will be acting as the rock slides on the surface of the pond. That force acts always opposite the direction of movement, therefore decelerating the rock. The rock's speed will continue reducing in magnitude until it eventually stops.

Then, the selected answer is: "The rock will slow down and eventually stop."

You might be interested in

vA child is in danger of drowning in the Merimac river. The Merimac river has a current of 3.1 km/hr to the east. The child is 0

ikadub [295]

Answer:

$d = 2.26 km$

Explanation:

Let the child is moving with speed same as the speed of water flow

So here the position of child with respect to flow must be zero

And if the boat start at an angle with the vertical

so its relative speed with flow of water is given as

$v_x = 24.8 sin\theta$

$v_y = 24.8 cos\theta$

now the time to reach the child is given as

$\frac{0.6}{24.8 cos\theta} = \frac{2.5}{24.8 sin\theta }$

so now we have

$\theta = 76.5 degree$

So the time to catch the child is given as

$t = \frac{0.6}{24.8 cos78.2}$

$t = 0.104 h$

So distance moved by it in 0.104 h

distance moved by the boat in upstream direction given as

$x = (24.8 sin 74.8 - 3.1)(0.104)$

$x = 2.18 km$

In y direction the displacement of boat is

$y = 0.6 km$

net displacement of the ball is given as

$d = \sqrt{x^2 + y^2}$

$d = \sqrt{2.18^2 + 0.6^2}$

$d = 2.26 km$

4 0

3 years ago

P.E

Vladimir79 [104]

Answer:

pagtalon?

Explanation:

because that had to be the answer

5 0

3 years ago

What is the force in N of an object that has a mass of 7 kilograms and an acceleration of 4 m/s/s

VMariaS [17]

Newton's 2nd law of motion: Force = (mass) x (acceleration)

If you want to move a 7-kg object with an acceleration of 4 m/s²,
then you will need to push it with (7 x 4) = 28 newtons of force.

4 0

3 years ago

Which wavelength produces fluorescence? Why do you think this wavelength produces fluorescence while the other does not?

Maurinko [17]

Answer:

Long wavelength

Explanation:

Wavelengths that corresponds to the bands of blue and red are strongly absorbed whereas the wavelengths that lie in the mid-range corresponds to green light that are absorbed weakly.

Fluorescence produced is always directed towards longer wavelengths of the spectra as compared to the corresponding spectra for absorption.

4 0

3 years ago

Light bulb 1 operates with a filament temperature of 3000 K, whereas light bulb 2 has a filament temperature of 2000 K. Both fil

MatroZZZ [7]

Answer:

A₁/A₂ = 0.44

Explanation:

The emissive power of the bulb is given by the formula:

P = σεAT⁴

where,

P = Emissive Power

σ = Stefan-Boltzman constant

ε = Emissivity

A = Surface Area

T = Absolute Temperature of Surface

FOR BULB 1:

Since, emissivity and emissive power are constant.

Therefore,

P = σεA₁T₁⁴ ----------- equation 1

where,

A₁ = Surface Area of Bulb 1

T₁ = Temperature of Bulb 1 = 3000 k

FOR BULB 2:

Since, emissivity and emissive power are constant.

Therefore,

P = σεA₂T₂⁴ ----------- equation 2

where,

A₂ = Surface Area of Bulb 2

T₂ = Temperature of Bulb 1 = 2000 k

Dividing equation 1 by equation 2, we get:

P/P = σεA₁T₁⁴/σεA₂T₂⁴

1 = A₁(3000)²/A₂(2000)²

A₁/A₂ = (2000)²/(3000)²

A₁/A₂ = 0.44

6 0

3 years ago