Answer them all please!!

To measure the height of a building without a ruler or tape measure, an engineer drops a rock off the top of the building and fi

serg [7]

The relevant equation we can use in this problem is:

h = v0 t + 0.5 g t^2

where h is height, v0 is initial velocity, t is time, g is gravity

Since it was stated that the rock was drop, so it was free fall and v0 = 0, therefore:

h = 0 + 0.5 * 9.81 m/s^2 * (4.9 s)^2

6 0

3 years ago

Which of the following statements is true?

zhuklara [117]

A. You are exposed to nuclear radiation every day.

7 0

3 years ago

Read 2 more answers

We can see our face clearly on mirror why cant we see our face clear on aluminium or irion plate

Simora [160]

Because specular reflection occurs with a mirror, while diffuse reflection occurs with aluminium or iron plate

Explanation:

Reflection is a phenomenon typical of waves (such as light wave), that occurs when a wave bounces off the surface of a certain material, going back into the original medium at a certain angle, without changing speed, frequency or wavelength.

The direction of the reflected ray is given by the law of reflection, which states that:

The incoming ray, the reflected ray and the normal to the surface all lie on the same plane
The angle of incidence is equal to the angle of reflection

Depending on the type of surface, two different types of reflection can occur:

Specular reflection: this occurs when the surface is perfectly smooth. In such a case, all the incoming rays of light hit the surface with same angle of incidence, therefore they are reflected at the same angle. This means that a perfect and clear image of the original object can be formed: this is the case of a mirror.
Diffuse reflection: when the surface is not smooth, the imperfections on the surface are such that the incoming rays of light hit the surface at different angles of incidence. As a result, the rays are reflected at different angles to each other, and therefore no clear image of the object is produced. This is the case of aluminium or iron plate.

Learn more about reflection and other wave phenomena:

brainly.com/question/3183125

brainly.com/question/12370040

#LearnwithBrainly

8 0

3 years ago

The moment of inertia of a thin ring of mass M and radius R about its symmetry axis is ICM = MR2.

monitta

Answer:

The moment of inertia of large ring is 2MR².

(A) is correct option.

Explanation:

Given that,

Mass of ring = M

Radius of ring = R

Moment of inertia of a thin ring = MR²

Moment of inertia :

Moment of inertia is the product of the mass of the ring and square of radius of the ring.

We need to calculate the moment of inertia of large ring

Using formula of moment of inertia

$I=I_{cm}+MR^2$

Where, $I_{cm}$ = moment of inertia at center of mass

M = mass of ring

R = radius of ring

Put the value into the formula

$I=MR^2+MR^2$

$I=2MR^2$

Hence, The moment of inertia of large ring is 2MR².

6 0

3 years ago

A single conservative force F = (7.0x - 11) N, where x is in meters, acts on a particle moving along an x axis. The potential en

Umnica [9.8K]

Answer:

(a) 34.6429J

(b) -1.57 m

(c) 4.71 m

Explanation:

The derivative of the potential energy with respect to the position is equal to the negative of the force, so:

$-\frac{dU}{dx}=F\\ dU=-Fdx$

Then, if we integer both sides, we get:

∫dU = -∫(7x - 11)dx

$U=\frac{-7}{2}x^{2} + 11x + c$

we know that U is equal to 26 J when x is zero, so:

$U=\frac{-7}{2}x^{2} + 11x + c$

$26=\frac{-7}{2}(0)^{2} + 11(0) + c$

$26=c$

Finally, the equation for the potential energy is:

$U(x)=\frac{-7}{2}x^{2} + 11x + 26$

Therefore, the maximum positive potential energy is the energy when x is equal to 11/7. That is because the equation of U is the equation of a parable, and the vertex in a parable is given by:

$x=\frac{-b}{2a} = \frac{-11}{2(-7/2)} =\frac{11}{7}$