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3 years ago

Which statement is a scientific law?

Physics

2 answers:

gavmur [86]3 years ago

6 0

a. Scientists use genes to explain why evolution works

oksian1 [2.3K]3 years ago

4 0

A. because it's been repeated multiple times

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A 0.30-m-radius automobile tire accelerates from rest at a constant 2.0 rad/s2. What is the centripetal acceleration of a point

lianna [129]

Answer:

The centripetal acceleration is 30 m/s²

Explanation:

Given that,

Radius = 0.30 m

Acceleration = 2.0 rad/s²

Time = 5.0

We need to calculate the centripetal acceleration

Using formula of angular velocity

$\omega=a\times t$

Where,

a = acceleration

t = time

Put the value into the formula

$\omega=2.0\times5.0$

$\omega=10\ rad/s$

Using formula of centripetal acceleration

$a_{c}=r\omega^2$

$a_{c}=0.30\times10^2$

$a_{c}=30\ m/s^2$

Hence, The centripetal acceleration is 30 m/s²

8 0

3 years ago

What is the frequency of radiation whose wavelength is 0.80 nm ? express the frequency in inverse seconds to three significant d

Mashcka [7]

The relationship between the frequency (f) of an electromagnetic wave, the speed of the wave (which is the speed of light, c) and its wavelength $\lambda$ is given by
$f= \frac{c}{\lambda}$

Since the wavelength of the radiation in the problem is $\lambda= 0.80 nm = 0.80 \cdot 10^{-9} m$ , by substituting numbers in the formula we can get the frequency:
$f= \frac{3 \cdot 10^8 m/s}{0.80 \cdot 10^{-9} m} =3.75 \cdot 10^{17} s^{-1}$

5 0

3 years ago

Plz helppppppp I need helpppppp

Svetach [21]

8 0

4 years ago

gives the speed v versus time t for a 0.500 kg object of radius 6.00 cm that rolls smoothly down a 30° ramp. The scale on the ve

ddd [48]

Answer:

Rotational inertia of the object is given as

$I = 7.2 \times 10^{-4} kg m^2$

Explanation:

As we know that the acceleration of the object on inclined plane is given as

$a = \frac{gsin\theta}{1 + k^2/R^2}$

now we know that velocity at any instant of time is given as

$v = at$

now we know that if the graph between velocity and time is given then the slope of the graph will be same as acceleration

so here we have

$\frac{gsin\theta}{1 + k^2/R^2} = slope$

now from the graph slope of the graph is given as

$slope = \frac{3.5 - 0}{1}$

$\frac{gsin\theta}{1 + k^2/R^2} = 3.5$

$\frac{9.81 sin30}{1 + k^2/R^2} = 3.5$

$k^2 = 0.4 R^2$

now rotational inertia is given as

$I = mk^2$

$I = 0.5(0.4)(0.06)^2$

$I = 7.2 \times 10^{-4} kg m^2$

8 0

4 years ago

A 1300 kg car moving at 20 m/s and a 900 kg car moving at 15 m/s in precisely oppositedirections participate in a head-on crash.

miskamm [114]

Given

Car 1

m1 = 1300 kg

v1 = 20 m/s

m2 = 900 kg

v2 = -15 m/s

(Negative sign shows that direction of car 2 is opposite to car 1)

Procedure

As per the conservation of linear momentum, "The total momentum of the system before the collision must be equal to the total momentum after the collision". And this applies to the perfectly inelastic collision as well. Then the expression is,

$\begin{gathered} m_1v_1+m_2v_2=(m_1+m_2)v \\ v=\frac{m_1v_1+m_2v_2}{m_1+m_2} \\ v=\frac{1300\operatorname{kg}\cdot20m/s-900\operatorname{kg}\cdot15m/s}{1300\operatorname{kg}+900\operatorname{kg}} \\ v=5.681m/s \end{gathered}$

Thus, we can conclude that the speed and direction of the cars after the impact is 5.68 m/s towards the first car.

5 0

1 year ago