What kind of mirror is used in automobiles and trucks

An electron in a(n) __________ subshell experiences the greatest effective nuclear charge in a many-electron atom.

bixtya [17]

The electrons float around in an outer sub shell

6 0

3 years ago

If a force does a positive amount of work on an object, does the object's speed

Alexxandr [17]

The speed of the object increases

Explanation:

We can answer this question by applying the work-energy theorem, which states that the work done on an object is equal to the change in kinetic energy of the object. Mathematically:

$W=K_f -K_i= \frac{1}{2}mv^2-\frac{1}{2}mu^2$

where

W is the work done on the object

$K_f, K_i$ are the final and initial kinetic energy of the object, respectively

m is the mass of the object

v is its final speed

u is its initial speed

In this case, the force does a positive amount of work on the object, so

$W>0$

This also implies that

$K_f > K_i$

And so

$\frac{1}{2}mv^2 > \frac{1}{2}mu^2$

And therefore

$v>u$

which means that the speed of the object increases.

Learn more about work:

brainly.com/question/6763771

brainly.com/question/6443626

#LearnwithBrainly

8 0

3 years ago

A 128 gram Radium-226 sample with a half-life of 2.25 billion years is found. How many grams will remain after two half-lives?

Bess [88]

Answer:

Option B. 32 g

Explanation:

From the question given above, the following data were obtained:

Original amount (N₀) = 128 g

Half-life (t½) = 2.25 billion years

Number of half-lives (n) = 2

Amount remaining (N) =?

The amount of 128 gram of Radium-226 that will remain after 2 half-lives has elapsed can be obtained as followb

N = 1/2ⁿ × N₀

N = 1/2² × 128

N = 1/4 × 128

N = 0.25 × 128

N = 32 g

Therefore, 32g of the sample will remain.

8 0

3 years ago

Two particles with oppositely signed charges are held a fixed distance apart. The charges are equal in magnitude and they exert

damaskus [11]

Answer:

the force will decrease to 3/4 of its original value.

Explanation:

The initial electric force between the two charges is:

$F = k \frac{q\cdot q}{r^2}$

where

k is the Coulomb's constant

q is the magnitude of each charge

r is their separation

Later, half of one charge is transferred to the other charge; this means that one charge will have a charge of

$q+\frac{q}{2}=\frac{3}{2}q$

while the other charge will be

$q-\frac{q}{2}=\frac{q}{2}$

So, the new force will be

$F' = k \frac{(\frac{q}{2})\cdot (\frac{3}{2}q)}{r^2}=\frac{3}{4} (k\frac{q\cdot q}{r^2})=\frac{3}{4}F$

So, the force will decrease to 3/4 of its original value.

6 0

3 years ago

An unruly student with a spitwad (a lump of wet paper) of mass 20 g in his pocket finds himself in the school library where ther

jeka94

Answer:

T = 188.5 s, correct is C

Explanation:

This problem must be worked on using conservation of angular momentum. We define the system as formed by the fan and the paper, as the system is isolated, the moment is conserved

initial instant. Before the crash

L₀ = r m v₀ + I₀ w₀

the angular speed of the fan is zero w₀ = 0

final instant. After the crash

L_f = I₀ w + m r v

L₀ = L_f

m r v₀ = I₀ w + m r v

angular and linear velocity are related

v = r w

w = v / r

m r v₀ = I₀ v / r + m r v

m r v₀ = (I₀ / r + mr) v

v = $\frac{m}{\frac{I_o}{r} +mr} \ r v_o$

let's calculate

v = $\frac{0.020}{\frac{1.4}{0.6 } + 0.020 \ 0.6 } \ 0.6 \ 4$

v = $\frac{0.020}{2.345} \ 2.4$

v = 0.02 m / s

To calculate the time of a complete revolution we can use the kinematics relations of uniform motion

v = x / T

T = x / v

the distance of a circle with radius r = 0.6 m

x = 2π r

we substitute

T = 2π r / v

let's calculate

T = 2π 0.6/0.02

T = 188.5 s

reduce

t = 188.5 s ( 1 min/60 s) = 3.13 min

correct is C

6 0

3 years ago