All categories

2 years ago

IF U ANSWER I WILL MARK U BRAINLLIEST

Physics

2 answers:

notka56 [123]2 years ago

8 0

A) The density of a substance or object is a measure of how compact the mass is.
B) Objects that are more dense than water sink and those less dense float.
C) This weight-to-volume ratio is referred to as density. Water can support an object that is less dense than water, allowing it to float. An object that is denser than water sinks.
II A) These three elements are all metals, but they have different molecular masses, atomic weights, and atomic numbers. Similarly, all three of them have luster and are good conductors of electricity.

goldfiish [28.3K]2 years ago

6 0

Explanation:

a) Density is the amount of mass in a specific amount of volume

b) Some substances are less dense than water so will float and vice versa

c) The wooden plank has less density than water due to having larger volume and vice versa with the wooden block since volume and density are inversely proportional

II) (a) They are all metals

(b) water -> Compound

oxygen -> Element

Gold-> Element

Salt-> Compound

You might be interested in

Determine whether or not each of the following statement is true. If a statement is true, prove it. If the statement is false, p

Studentka2010 [4]

Answer:

True

Explanation:

This is a representation of Gauss law.

Gauss’s law does hold for moving charges, and in this respect Gauss’s law is more general than Coulomb’s law. In words, Gauss’s law states that: The net outward normal electric flux through any closed surface is proportional to the total electric charge enclosed within that closed surface. The law can be expressed mathematically using vector calculus in integral form and differential form, both are equivalent since they are related by the divergence theorem, also called Gauss’s theorem.

8 0

3 years ago

There is a uniform magnetic field of magnitude B, pervading all space, perpendicular to the plane of rod and rails. The rod is r

Charra [1.4K]

The right hand rule to find the direction of the magnetic field for a falling bar is:

The charge is positive the magnetic field is outgoing, horizontally and towards us.

The charge of the bar is negative, the magnetic field is incoming, that is horizontal away from us.

The magnetic force is given by the vector product of the velocity and the magnetic field.

F = q v x B

Where the bolds indicate vectors, F is the force, q the charge on the particle, v the velocity and B the magnetic field.

In the vector product, the vectors are perpendicular, which is why the right-hand rule has been established, see attached:

The thumb points in the direction of speed.

Fingers extended in the direction of the magnetic field.

The palm is in the direction of the force if the charge is positive and in the opposite direction if the charge is negative.

They indicate that the bar is dropped, therefore its speed is vertical and downwards, it moves to the left therefore this is the direction of the force, we use the right hand rule, the magnetic field must be horizontal, we have two possibilities:

If the charge is positive the magnetic field is outgoing, horizontally and towards us.

If the charge of the bar is negative, the magnetic field is incoming, that is, horizontal away from us

In conclusion using the right hand rule we can find the direction of the magnetic field for a falling bar is:

The charge of the bar is negative, the magnetic field is incoming, that is horizontal away from us.

The charge is positive the magnetic field is outgoing, horizontally and towards us.

Learn more about the right hand rule here: brainly.com/question/12847190

6 0

2 years ago

Why is polaris used as a celestial reference point?

ser-zykov [4K]

At the equator, the North Celestial and South Celestial Poles would lie on the horizon where the meridian intersects the horizon. Polaris is called the "North Star." ... Polaris is special because the Earth's North Pole points almost exactly towards it.

8 0

2 years ago

child slides down a snow‑covered slope on a sled. At the top of the slope, her mother gives her a push to start her off with a s

Strike441 [17]

Answer:

θ = 13.7º

Explanation:

According to the work-energy theorem, the change in the kinetic energy of the combined mass of the child and the sled, is equal to the total work done on the object by external forces.
The external forces capable to do work on the combination of child +sled, are the friction force (opposing to the displacement), and the component of the weight parallel to the slide.
As this last work is just equal to the change in the gravitational potential energy (with opposite sign) , we can write the following equation:

$\Delta K + \Delta U = W_{nc} (1)$

ΔK, is the change in kinetic energy, as follows:

$\Delta K = \frac{1}{2}* m* (v_{f} ^{2} - v_{0} ^{2}) (2)$

ΔU, is the change in the gravitational potential energy.
If we choose as our zero reference level, the bottom of the slope, the change in gravitational potential energy will be as follows:

$\Delta U = 0 - m*g*h = -m*g*d* sin\theta (3)$

Finally, the work done for non-conservative forces, is the work done by the friction force, along the slope, as follows:

$W_{nc} = F_{f} * d * cos 180\º \\\\ = 0.2*m*g*d* cos 180\º = -0.2*m*g*d (4)$

Replacing (2), (3), and (4) in (1), simplifying common terms, and rearranging, we have:

$\frac{1}{2}* (v_{f} ^{2} - v_{0} ^{2}) = g*d* sin\theta -0.2*g*d$

Replacing by the givens and the knowns, we can solve for sin θ, as follows: $\frac{1}{2}*( (4.30 m/s) ^{2} - (0.75 m/s)^{2}) = 9.8 m/s2*25.5m* sin\theta -0.2*9.8m/s2*25.5m\\ \\ 8.56 (m/s)2 = 250(m/s)2* sin \theta -50 (m/s)2\\ \\ sin \theta = \frac{58.6 (m/s)2}{250 (m/s)2} = 0.236$ ⇒ θ = sin⁻¹ (0.236) = 13.7º