can someone please help me answer this question ?

Answer:

I believe it is D

forgive me if I'm wrong

Answer:

7.5 cm behind the mirror

Explanation:

Applying,

Using the real is positive convection: All real distance from the mirror are positive

1/f = 1/v+1/u................. Equation 1

Where f = focal length of the mirror, v = image distance, u = object distance

From the question,

f = -12 cm, u = 20 cm

substitute these value into equation 1

1/(-12) = (1/20)+1/v

(-1/12)-(1/20) = 1/v

1/v = (-5-3)/60

1/v = -8/60

v = -60/8

v = -7.5 cm

Hence the image is formed 7.5 cm behind the mirror.

Power of TV = 65Watt

If Efficiency = 70%, then the percentage of energy wasted is 30%

So, the amount of energy getting wasted:

= 30/100 × 65

= 1950/100

= 195/10

= 19.5 W

Answer:

The second one.

Explanation:

It caused both to change speed because they have both the same mass.

Answer:

Evaporation

Explanation:

Erosion is a natural process, but human activity can make it happen more quickly. Human activity altering the vegetation of an area is perhaps the biggest human factor contributing to erosion. Trees and plants hold soil in place.

Factor that contributes the most to the process of water erosion is Evaporation. The correct option is A.

Evaporation is the phenomenon of converting the liquid into gas phase by the addition of heat energy.

Erosion is also a natural phenomenon. Trees and plants hold soil in place and prevents the soil erosion. Just like that, the water erosion happens when more than natural evaporation happens due to increased heat by various factors.

Thus, Evaporation contributes the most to the process of water erosion. The correct option is A.

Answer:

She will have kinetic energy at the bottom of the hill=45700 J

Explanation:

We are given that

Mass, m=60 kg

Speed, v=10 m/s

Height, h=150 m

Length of slope, d=650 m

Frictional force, f=70 N

We have to find the kinetic energy she will have at the bottom of the hill.

Kinetic energy  at the bottom of the hill

=Initial kinetic energy+ mgh-fd

Substitute the values

Kinetic energy  at the bottom of the hill

=[tex]\frac{1}{2}(60)(10)^2+60\times 9.8\times 150-70\times 650[/tex]

=[tex]45700J[/tex]

Hence, she will have kinetic energy at the bottom of the hill=45700 J

Answer:

a) v₂ = 4.2 m/s

b) v₂ = 5 m/s

Explanation:

a)

We will use the law of conservation of momentum here:

[tex]m_1u_1+m_2u_2=m_1v_1+m_2v_2[/tex]

where,

m₁ = m₂ = mass of bowling pin = 1.8 kg

u₁ = speed of first pin before collsion = 5 m/s

u₂ = speed of second pin before collsion = 0 m/s

v₁ = speed of first pin after collsion = 0.8 m/s

v₂ = speed of second after before collsion = ?

Therefore,

[tex](1.8\ kg)(5\ m/s)+(1.8\ kg)(0\ m/s)=(1.8\ kg)(0.8\ m/s)+(1.8\ kg)(v_2)\\v_2 = 5\ m/s - 0.8\ m/s[/tex]

v₂ = 4.2 m/s

b)

We will use the law of conservation of momentum here:

[tex]m_1u_1+m_2u_2=m_1v_1+m_2v_2[/tex]

where,

m₁ = m₂ = mass of bowling pin = 1.8 kg

u₁ = speed of first pin before collsion = 5 m/s

u₂ = speed of second pin before collsion = 0 m/s

v₁ = speed of first pin after collsion = 0 m/s

v₂ = speed of second after before collsion = ?

Therefore,

[tex](1.8\ kg)(5\ m/s)+(1.8\ kg)(0\ m/s)=(1.8\ kg)(0\ m/s)+(1.8\ kg)(v_2)[/tex]

v₂ = 5 m/s

Answer: 400 m

Explanation:

Vf= 20 + (4*10)

Vf= 60 [m/s]

x= (60^2 - 20^2) / (2*4)

x= 400 m

Answer:

Explanation:

[tex]a = \frac{v_f-v_0}{t}[/tex] which is the final velocity minus the initial velocity in the numerator, and the change in time in the denominator.  For us:

[tex]a=\frac{2.7-1.6}{1.2}[/tex] so

a = .92 m/s/s (NOT negative because you're speeding up)

Answer:

A short circuit is an abnormal connection between two nodes of an electric circuit intended to be at different voltages. This results in an electric current limited only by the Thévenin equivalent resistance of the rest of the network which can cause circuit damage, overheating, fire or explosion.

hope it helps.Please give me brainliest O:-)

Answer:

A short circuit is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance.

20 km

Hope this helps Have a good day

P = W / t

2000 = 30000 / t

t = 30000/2000

t = 30/2

t = 15 seconds

Explanation:

work(w)=30000J

power(p)=2000W

time taken(t)=?

now,

hope it helps.

Answer:

Linear magnification = 1/3

Explanation:

Given:

Convex mirror

Object's distance from pole = 2f

Find:

Linear magnification

Computation:

Object distance, u = −2f

So,

1/v + 1/u = 1/f

1/v + 1/(-2f) = 1/f

1/v = 1/f + 1/2f

BY taking LCM

1/v = 3 / 2f

v = 2f / 3

Magnification, M = -v / u

So,

Magnification, M = (2f / 3) / 2f

Magnification, M = 2f / 6f

Magnification, M = 2 / 6

Linear magnification = 1/3

Answer:

Living it:) thats all

Answer:

17.27 Hz

Explanation:

Applying

v = λf................ Equation 1

Where v = speed of the car, λ = Distance between successive crevice, f = number of crevice moved in 1 seconds(Frequency of the vibration)

make f the subject of the equation

f = v/λ............. Equation 2

From the question,

Given: v = 38 m/s, λ = 2.2 m

Substitute these values into equation 2

f = 38/2.2

f = 17.27 Hz

Answer:

8.136×10⁻⁵ J

Explanation:

Applying,

Q = Cv................ Equation 1

Where Q = Charge on the capacitor, v = voltage of the battery, C = capacitance of the capacitor.

From the question,

Given: C = 6.78μF = 6.78×10⁻⁶ F, v = 12 V

Substitute these values into equation 1

Q = (6.78×10⁻⁶ )(12)

Q = 8.136×10⁻⁵ J

Hence the charge on the capacitor is 8.136×10⁻⁵ J

Answer:

the type of force is Unbalanced force;

As upward force is not equal to downward force.

Answer:

10m/hr

Explanation:

10m/3600 sec= 1m/360sec

Answer:

Capacitance is a derived physical quantity measured in farad

Answer:

"Farad" is another term for the coulomb/volt measurement of capacitance, so both of those options are the correct answer. Amperes and coulomb/second are measurements of electric flow, in other words, how strong a current is.

Answer:

False

Explanation:

parts that are smaller than protons neutrons and electrons

Answer:

I am not sure if this is the answer

(B) what is the height of the building if it hits the ground after those 5 seconds.

Answer:

The fundamental units are the base units defined by International System of Units. These units are not derived from any other unit, therefore they are called fundamental units. The seven base units are: Meter (m) for Length. Second (s) for Time.

Explanation:

Answer:

420J

Explanation:

Power is the time rate of change in energy. Power is the ratio of energy to time. The S.I unit of power is in watts.

Given that the flash lasts for 1/675 s, power output is 2.7 * 10⁵ W. Hence:

Power = Energy / time

Substituting:

2.7 * 10⁵ W = Energy / (1/675)

Energy = 2.7 * 10⁵ W * 1/675 = 400J

Therefore the energy emitted as light is 400J.

Since the conversion of electric energy to light is 95% efficient, hence the energy stored as electrical energy is:

Energy(capacitor) = 5% of 400J + 400J = 0.05*400 + 400

Energy(capacitor) = 420J

29900 J

Explanation:

Recall that

P = VI

= (230 volts)(13 A)

= 2990 watts

Also,

E = Pt

= (2990 watts)(10 s)

= 29900 J

Answer:

Perform a simple test of the material in the pan to assess whether it is real gold. Raw gold appears brassy yellow and bright. If you think it is gold, place your hand between it and the sun to create shade over the gold. If it still appears bright in the pan, chances are that it is real gold.

Explanation: