All categories

2 years ago

Plssss help I need good grade!!!! Plssss and thank u

Physics

2 answers:

shepuryov [24]2 years ago

8 0

Answer:

the answer is 'b'

According to me

Tatiana [17]2 years ago

8 0

Answer:

Explanation:

It has more negative signs than positive signs

You might be interested in

Part A.)Six boxes held at rest against identical walls.

krok68 [10]

Answer:

Explanation:

When a body is held against a vertical wall , to keep them in balanced position , normal force is applied on their surface . this force creates normal reaction which acts against the normal force and it is equal to the normal force as per newton's third law . Ultimately friction force is created which is proportional to normal force and it acts in vertically upward direction . It prevents the body from falling down .

Hence normal force = reaction force .

From second law also net force is zero , so if normal force is N and reaction force is R

R - N = mass x acceleration = mass x 0 = 0

R = N .

Ranking normal force from highest to smallest

150 N , 130 N , 120 N

B )

Frictional force is equal to the weight of the body because the body is held at rest .

Ranking of frictional force form largest to smallest

7 kg , 5 kg , 3 kg , 1 kg .

Here frictional force is irrespective of the normal force acting on the body because frictional force adjusts itself so that it becomes equal to weight in all cases here because it always balances the weight of the body .

6 0

3 years ago

Calculate the amount of heat liberated (in kj) from 411 g of mercury when it cools from 88.0°c to 12.0°c.

Katen [24]

You should note that the melting point of mercury is -38.83°C, while the boiling point is at 356.7°C. Then, that means that there is no latent heat involved here. We only compute for the sensible heat.

ΔH = mCpΔT
The Cp of mercury is 0.14 J/g·°C
Thus,
ΔH = (411 g)(0.14 J/g·°C)(88 - 12°C)
<em>ΔH = 4,373.04 J</em>

5 0

3 years ago

What is the period of a wave that has a frequency of 300 hz?

Butoxors [25]

Answer:

T = 0.003 s

(Period is written as T)

Explanation:

Period = time it takes for one wave to pass (measured in seconds)

frequency = number of cycles that occur in 1 second

(measured in Hz / hertz / 1 second)

Period : T

frequency : f

So, if we know that the frequency of a wave is 300 Hz, we can find the period of the wave from the relation between frequency and period

T = $\frac{1}{f}$ f = $\frac{1}{T}$

to find the period (T) of this wave, we need to plug in the frequency (f) of 300

T = $\frac{1}{300}$

T = 0.00333333333

So, the period of a wave that has a frequency of 300 Hz is 0.003 s

[the period/T of this wave is 0.003 s]

3 0

1 year ago

How many hydrogen atoms are in a water molecule?

earnstyle [38]

The subscript after the element indicates the number of atoms of that element in the molecule. So, in H20, the subscript after the H, which stands for hydrogen, is 2. This means that there are 2 hydrogen atoms in a water molecule.

Hope this helps! :)

4 0

3 years ago

What is the electric potential energy of a charge that experiences a force of 3.6 x 10^-4N when it is 9.8 x 10^-5 from the sourc

Levart [38]

The electric potential energy of the charge is equal to the potential at the location of the charge, V, times the charge, q:
$U=qV$
The potential is given by the magnitude of the electric field, E, times the distance, d:
$V=Ed$
So we have
$U=qEd$ (1)
However, the electric field is equal to the electrical force F divided by the charge q:
$E= \frac{F}{q}$
Therefore (1) becomes
$U=Fd$
And if we use the data of the problem, we can calculate the electrical potential energy of the charge:
$U=Fd=(3.6 \cdot 10^{-4}N)(9.8 \cdot 10^{-5} m)=3.53 \cdot 10^{-8} J$

7 0

3 years ago