Which phases of matter do molecules have the lowest amount of energy?

Which of the following are true about centripetal force? Check all that apply. A. Without centripetal force, an object cannot ac

Katyanochek1 [597]

B. Friction can be a centripetal force, such as when it keeps a car on the road going around a curve.

C. Gravity can be a centripetal force, such as when it pulls a satellite in its orbit.

Explanation:

The centripetal force is any force that keeps an object moving in circular motion, "pulling" the object towards the centre of the circular trajectory.

Several forces can act as centripetal force. Examples are:

- friction: when a car is going around the curve, is moving by circular motion. The force that keeps the car in circular motion is, in fact, the friction between the tires and the road.

- Gravity: when a satellite moves around the Earth, it is moving by circular motion. The force that keeps the satellite in circular motion is the gravitational attraction between the Earth and the satellite, that pushes the satellite towards the Earth.

The other two options are not correct because:

A) An object can also accelerate if there is no centripetal force (for example, a car speeding up on a straight road is accelerating, but there is no centripetal force since there is no circular motion

D) Centripetal force is not an outward force, since it pushes the object inwards (towards the centre of the trajectory).

3 0

3 years ago

Read 2 more answers

En un m.A.S. La amplitud tiene un valor de 10 centimetros y el periodo es de 2 segundos calcular el valor de la velocidad de 0.8

Ivanshal [37]

Answer:

v1=18.46m/s

v2=29.8cm/s

Explanation:

We know that

$A=10cm\\T=2s$

the equation of the motion is

$x=Acos(\omega t)\\$

we can calculate w by using

$\omega=\frac{2\pi}{T}=\frac{2\pi}{2}=\pi$

Hence, we have that

$x=10cm*cos(\pi t)\\$

the speed will be

$v=-\omega*Asin(\omega t)\\|v(0.8)|=|\pi*10cm*sin(\pi *0.8)|=18.46\frac{cm}{s}\\|v(1.4)|=|\pi*10cm*sin(\pi *1.4)|=29.8\frac{cm}{s}$

hope this helps!

6 0

3 years ago

A block is resting on a platform that is rotating at an angular speed of 2.4 rad/s. The coefficient of static friction between t

Sloan [31]

Answer:

r = 0m is the Minimum distance from the axis at which the block can remain in place wothout skidding.

Explanation:

From a sum of forces:

$Ff = m*a$ where Ff = μ * N and $a = \frac{V^2}{r}=\omega^2*r$

N - m*g = 0 So, N = m*g. Replacing everything on the original equation:

$\mu*m*g = m*\omega^2*r$ (eq2)

Solving for r:

$r = \frac{\mu*g}{\omega^2}=1.41m$

If we analyze eq2 you can conclude that as r grows, the friction has to grow (assuming that ω is constant), so the smallest distance would be 0 and the greatest 1.41m. Beyond that distance, μ has to be greater than 0.83.

4 0

3 years ago

What is the period of a simple pendulum 47 cm long (a) on the Earth, and ( b) when it is in a freely falling elevator?

Liula [17]

Answer:

a)1.37 s

b)∞ ( Infinite)

Explanation:

Given that

L= 47 cm ( 1 m =100 cm)

L= 0.47 m

a)

On the earth :

Acceleration due to gravity = g

We know that time period of the simple pendulum given as

$T=2\pi\sqrt{ \dfrac{L}{g_{{eff}}}$

Here

$g_{eff}= g$

Now by putting the values

$T=2\pi \times\sqrt{ \dfrac{0.47}{9.81}}$

T=1.37 s

b)

Free falling elevator :

When elevator is falling freely then

$g_{eff}= 0$ ( This is case of weightless motion)

Therefore

$T=2\pi\sqrt{ \dfrac{L}{0}$

T=∞ (Infinite)

6 0

3 years ago

The first artificial satellite to orbit the Earth was Sputnik I, launched October 4, 1957. The mass of Sputnik I was 83.5 kg, an

9966 [12]

Answer:

$-4.941*10^8J.$

Explanation:

To solve this exercise it is necessary to take into account the concepts related to gravitational potential energy, as well as the concept of perigee and apogee of a celestial body.

By conservation of energy we know that,

$\Delta U = \Delta_{perogee}-\Delta_{Apogee}$