All categories

3 years ago

On the seashore, pebbles that are rough and uneven become smooth and rounded. Explain how the become smooth and rounded.

2 answers:

8 0

Pebbles usually become smooth and rounded by being polished by water, sand polished by winds, or by tumbling and exposing other sides to erosive effects.

7nadin3 [17]3 years ago

6 0

The sea smooths it by washing over it lots

You might be interested in

A Pitot-static probe is used to measure the speed of an aircraft flying at 3000 m. If the differential pressure reading is 3300

adell [148]

Answer:

v = 306.76 Km/h

Explanation:

given,

height of the aircraft = 3000 m

differential pressure reading = 3300 N/m²

density of air = 0.909 Kg/m³

speed of aircraft = ?

Assuming the air flowing above air craft is in-compressible, irrotational and steady so, we can use Bernoulli's equation to solve the problem.

using Bernoulli's equation

$\dfrac{v^2}{2} = \dfrac{\Delta P}{\rho}$

where ρ is the density of the air at 3000 m

$v= \sqrt{\dfrac{2 \times \Delta P}{\rho}}$

$v= \sqrt{\dfrac{2 \times 3300}{0.909}}$

$v = \sqrt{7260.726}$

v = 85.21 m/s

$v= 85.21 \times \dfrac{3600}{1000}$

v = 306.76 Km/h

4 0

3 years ago

Investigations allow for the control of variables.

Mila [183]

Dependent / Response Variable: factor or condition in a experiment that changes as a result of the independent variable; often called the responding variable. ... Constant: factors or conditions in an experiment that are kept the same in as trials of the experiment. Control: a set up without the variable being tested.

6 0

3 years ago

A car of mass 900 kg is traveling at 20 m/s when the brakes are applied. The car then comes to a complete stop in 5 s. What is t

ollegr [7]

Answer:

A. 36,000 W

Explanation:

$m$ = mass of the car = 900 kg

$v_{o}$ = Initial speed of the car = 20 m/s

$v_{f}$ = Final speed of the car = 0 m/s

$W$ = Work done by the brakes on the car

Magnitude of work done on the car by the brakes is same as the change in kinetic energy of the car.hence

$W = (0.5) m (v_{o}^{2} - v_{f}^{2})\\W = (0.5) (900) ((20)^{2} - (0)^{2})\\W = 180000 J$

$t$ = time taken by the car to come to stop = 5 s

$P$ = Average power produced by the car

Average power produced by the car is given as

$P = \frac{W}{t} =\frac{180000}{5} \\P = 36000 W$

8 0

3 years ago

A weightlifter curls a 25 kg bar, raising it each time a distance of 0.50 m. How many times must he repeat this exercise to burn

anyanavicka [17]

42 times must he repeat this exercise to burn off the energy in one slice of pizza.

What is energy?

Energy is the ability or capability to do tasks, such as the ability to move an item (of a certain mass) by exerting force. Energy can exist in many different forms, including electrical, mechanical, chemical, thermal, or nuclear, and it can change its form.

Energy burn by the weightlifter = potential energy

Potential energy = mgh

Potential energy = 25.(9.8)(0.50)

Potential energy = 122.5 Joule.

Assume 25% of efficiency so energy burn = 122.5*25/100

energy burn = 30.625 joule

Number of times = 1260/30.625

Number of times = 42 times.

42 times must he repeat this exercise to burn off the energy in one slice of pizza.

To learn more about energy refer to the link:

brainly.com/question/1932868

#SPJ1

6 0

2 years ago

A cat dozes on a stationary merry-go-round, at a radius of 4.6 m from the center of the ride. then the operator turns on the rid

ioda

<span>Radius = 4.6 m
Time for one complete rotation t = 5.5 s.
Distance = 2 x 3.14 x R = 2 x 3.14 x 4.6 m = 28.888.
Velocity V = distance / time = 28.888 / 5.5 s = 5.25 m/s
Force exerted by cat Fc = mV^2 / R = (mx 5.25^2) / 4.6 m
Force of the cat Fc = 6m, m being the mass.
Normal force = Us x m x g = Us x m x 9.81 = Us9.81m
equating the both forces => Us9.81m = 6m => Us = 6 / 9.81 => Us = 0.6116 So coefficient of static friction = 0.6116</span>

4 0

3 years ago