Is an electrical current which comes from a battery

During a race, a runner runs at a speed of 6 m/s. 2 seconds later, she is running at a speed of 10 m/s. What is the runner’s acc

Lina20 [59]

V o = 6 m/s,
t = 2 s
v = 10 m/s
v = v o + a t
a t = v - v o
a = ( v - v o ) / t
a = ( 10 m/s - 6 m/s ) / 2 s = 4 m/s / 2 s = 2 m/s²
Answer:
The runner`s acceleration is 2 m/s².

6 0

2 years ago

Given three vectors A = 24i + 33j, B = 55i - 12j and C = 2i + 43j (a) Find the magnitude of each vector. (b) Write an expression

slega [8]

Answer:

(a) , . and .

(b) $\vec A - \vec C=22 \hat i -10 \hat j$ .

(c) $|\vec A - \vec B|=63.13$ and the direction $\theta =$ 124.56°.

Explanation:

Given that,

,

and

$\vec {C}=2 \hat i +43 \hat j$

(a) The magnitude of a vector is the square root of the sum of the square of all the components of the vector, i.e. for a ,.

So, the magnitude of the is

$|\vec A|=\sqrt {24^2+ 33^2}$

$\Rightarrow |\vec A|=\sqrt {1665}$

.

The magnitude of the is

$|\vec B|=\sqrt {55^2+ (-12)^2}$

$\Rightarrow |\vec B|=\sqrt {3169}$

.

And, the magnitude of the is

$|\vec C|=\sqrt {2^2+ 43^2}$

$\Rightarrow |\vec C|=\sqrt {1853}$

.

(b) The difference between the two vectors is the difference between the corresponding components of the vectors. So, the required expression of is

$\vec A - \vec C=(24 \hat i +33 \hat j) - (2 \hat i +43 \hat j)$

$\Rightarrow \vec A - \vec C=24 \hat i +33 \hat j - 2 \hat i -43 \hat j$

$\Rightarrow \vec A - \vec C=22 \hat i -10 \hat j$

(c) The expression of is

$\vec A - \vec N=(24 \hat i +33 \hat j) - (55 \hat i -12 \hat j)$

$\Rightarrow \vec A - \vec B=24 \hat i +33 \hat j - 55\hat i +12 \hat j$

$\Rightarrow \vec A - \vec B=-31 \hat i +45 \hat j\;\cdots (i)$

The magnitude of is

$|\vec A - \vec B|=\sqrt {(-31)^2+55^2}$

$\Rightarrow |\vec A - \vec B|=\sqrt {3986}$

$\Rightarrow |\vec A - \vec B|=63.13$

Now, if a vector $\vec V= -\alpha \hat i +\beta \hat j$ in 3rd quadrant having direction $\theta$ with respect to $\hat i$ direction, than

in the anti-clockwise direction.

Here, from equation (i), for the vector $\vec A - \vec C$ , $\alpha=31$ and $\beta=45$ .

$\Rightarrow \theta = \pi-\tan ^{-1}\left(\frac {45}{31}\right)$

180°-55.44° [as \pi radian= 180°]

124.56° in the anti-clockwise direction.

(d) Vector diagrams for $\vec A +\vec B$ and $\vec A - \vec B$ has been shown

in the figure(b) and figure(c) recpectively.

Vector $\vec A - \vec B$ is in 3rd quadrant as calculated in part (c).

While Vector $\vec A +\vec B=(24 \hat i +33 \hat j)+(55 \hat i -12 \hat j)$

$\Rightarrow \vec A +\vec B=79 \hat i +21 \hat j$ , which is in 1st quadrant as both the components are position has been shown in figure(b).

6 0

2 years ago

Hi:) why do metals have free electrons? anyone able to explain the conduction part as well? Thanks!

Karo-lina-s [1.5K]

Metals have free electrons due to the bonding in metallic substances.

In a metal there are strong attractive forces between the nuclei and the valance electrons.

Positively charged metal nuclei form a lattice (a cube like structure) each metal atom provides one or more valance electrons that are free to move throughout the lattice The electrons are attracted to the positively charged nuclei but not one individual nuclei, this is called non-directional bonding since it occurs in all directions.

Now all metals are conductive becuase of the free to move (delocalised) electrons. Since the valance electrons are free to move throughout the lattice they are able to carry a charge. (Ionic solids cannot since the ionic solids form a tightly packed lattice with cations and anions which have no free moving electrons, electrons have to be able to move to carry a charge)

7 0

2 years ago

Two particles are separated by a certain distance. the force of gravitational interaction between them is f0. now the separation

12345 [234]

as i recall, gravity is relative to the square of the distance.

so if the distance is tripled, then the gravitational attraction would be reduced by 3^2 or 1/9.
so F1 = F0/9

if the satellite is 2R from the center, and is moved to 4R (doubled would be 3R, tripled is 4R) then the distance is twice, and gravity would be 2^2 or 1/4.

4 0

2 years ago

Read 2 more answers

What scientists do that is the basis of their investigations

matrenka [14]

The "scientific method" consists of forming a hypothesis (a statement about what the researchers think is true), collecting data that might confirm or refute the hypothesis, and then examining the data to see how well or poorly they support the original hypothesis.

3 0

3 years ago