Please help!!A camera lens 13.3 cm from a
flower makes an image at a
distance of 2.25 cm from the lens,
on the film. What is the focal
length of the lens?
(Unit = cm)

radiation

when the suns radiation fall on the earth and its objects they receive heat energy and hence get heated. Thus the suns heat reaches the earth by. the process of radiation

Absence of medium is the factor which shows that heat from the sun does reach the earth's surface by convection.

The heat of the sun reaches the earth only through radiation because radiation does not require any medium for the transfer of energy but convection and conduction required a medium to transfer heat energy.

We know that there is no medium present in vacuum so convection and conduction are impossible in a vacuum that's why the sun's heat does not reach the earth by conduction or convection.

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Answer:

t = 0.28 seconds

Explanation:

Given that,

Force acting on a firework, F = 700 N

The momentum of the firework, p =200 kg-m/s

We need to find the time before it explodes. Ket the time be t. We know that, the rate of change of momentum is equal to external frce. So,

[tex]F=\dfrac{P}{t}\\\\t=\dfrac{P}{F}\\\\t=\dfrac{200}{700}\\t=0.28\ s[/tex]

So, the required time is equal to 0.28 seconds.

Answer:

A. It is colder at the top of a mountain

Explanation:

Answer:

≈ 20.35 N [newton's of tension]

Explanation:

( (2.9 × 9.8) ÷ cos(35.6°) ) × sin (35.6°) =

( (28.42) ÷ (≈0.813) ) × (≈0.582) =

(≈34.96) × (≈0.582) = 20.3449446.... ≈ 20.35

Answer:

7.45 Ω

Explanation:

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

Resistor 1 (R₁) = 2.50 Ω

Resistor 2 (R₂) = 4.95 Ω

Voltage (V) = 12 V

Equivalent Resistance (Rₑq) =?

Since the resistors are in series arrangement, the equivalent resistance can be obtained as follow:

Rₑq = R₁ + R₂

Rₑq = 2.5 + 4.95

Rₑq = 7.45 Ω

Therefore, the equivalent resistance is 7.45 Ω

Answer:

Velocity (v) is a vector quantity that measures displacement (or change in position, Δs) over the change in time (Δt), represented by the equation v = Δs/Δt. Speed (or rate, r) is a scalar quantity that measures the distance traveled (d) over the change in time (Δt), represented by the equation r = d/Δt.

Explanation:

hope this helps a little bit sorry if i got it wrong

The resultant amplitude of the two waves is 1.0m

Resultant amplitude = 0.5m + 0.5m

Resultant amplutude = 1.0m

Hence the resultant amplitude of the two waves is 1.0m

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Answer:

Explanation:

Given that:

mass of the plastic ball = 50 g = 50 × 10⁻³ kg

spring constant (k) = 2.22 × 10⁵ N/m

compression of spring (x) = 3.0 cm = 3 × 10⁻² m

a) Work done:

[tex]= \dfrac{1}{2}kx^2 \\ \\ = \dfrac{1}{2}\times 2.22 \times 10^{5}\times (3 \times 10^{-2})^2 \\ \\ = 99.9 \ J[/tex]

b) When the gun is fired horizontally;

In the spring, the potential energy is changed to kinetic energy.

i.e.

[tex]\implies \dfrac{1}{2}kx^2 = \dfrac{1}{2}mv^2 \\ \\ 2.22 \times 10^5 \times (3\times 10^{-2}) ^2 =50 \times 10^{-3} \times v^2\\ \\ \mathbf{v= 63.2 m/s}[/tex]

c) The max height the bullet will reach if the gun is being shot upward is:

[tex]H_{max}= \dfrac{v^2}{2g} \\ \\ H_{max}= \dfrac{63.2^2}{2\times 9.8}[/tex]

[tex]\mathbf{H_{max}= 203.9 \ m}[/tex]

Answer:

white, blue and red

Explanation:

Force is given by

[tex]F=ma[/tex]

where

m = Mass of object

a = Acceleration of the object

If the acceleration is same for all the cars the force needed to be applied will depend on the mass of the car. The heaviest car requiring the most force and the lightest car requiring the least amount of force.

Here, the weight of the cars in descending order is white, blue and red.

So, the cars in order from the most to least amount of force needed to move them is white, blue and red.

Answer: Neap tides

Explanation: Neap tides are tides that have the smallest tidal range, and they occur when the Earth the Moon, and the Sun form a 90o angle. They occur exactly halfway between the spring tides when the Moon is at first or last quarter.

Answer:

1 m/s²

Explanation:

From the question,

Using

a = (v-u)/t.................... Equation 1

Where a = accelartion of the bicycle, v = Final velocity, u = initial velocity, t = time.

Given: v = 15 m/s, u = 5 m/s, t = 10 s

Substitute these values into equation 1

a = (15-5)/10

a = 10/10

a = 1 m/s²

Hence the acceleration of the bicycle is 1 m/s²

Answer:

4.83 °C

Explanation:

001 = λ*ΔT

ΔT = 10^-3*10^6/207 = 4.83°C

Answer:

4.83

Explanation:

Answer:

The average impact force is 12000 newtons.

Explanation:

By Impact Theorem we know that impact done by the sledge hammer on the chisel is equal to the change in the linear momentum of the former. The mathematical model that represents the situation is now described:

[tex]\bar F \cdot \Delta t = m \cdot (v_{2}-v_{1})[/tex] (1)

Where:

[tex]\bar F[/tex] - Average impact force, in newtons.

[tex]\Delta t[/tex] - Duration of the impact, in seconds.

[tex]m[/tex] - Mass of the sledge hammer, in kilograms.

[tex]v_{1}[/tex], [tex]v_{2}[/tex] - Initial and final velocity, in meters per second.

If we know that [tex]\Delta t = 0.0020\,s[/tex], [tex]m = 4\,kg[/tex], [tex]v_{1} = -6\,\frac{m}{s}[/tex] and [tex]v_{2} = 0\,\frac{m}{s}[/tex], then we estimate the average impact force is:

[tex]\bar F = \frac{m\cdot (v_{2}-v_{1})}{\Delta t}[/tex]

[tex]\bar F = 12000\,N[/tex]

The average impact force is 12000 newtons.

Answer:

the third one is incorrect

Explanation:

10 x 10³= 10^1 x 10^3 = 10^4

Answer:

increasing

Explanation:

Given that,

Initial angular speed =1 rad/s

Angular acceleration = 0.5 rad/s²

We know that the angular acceleration is given by :

[tex]\alpha =\dfrac{\omega_f-\omega_i}{t}[/tex]

Where

[tex]\omega_f[/tex]city and t is time is the final angualr velo

As the angular acceleration of the object is positive. It means that the final speed of the object is more than that initial. As a result, the speed of its rotation is increasing.

Answer:

Atoms are made up of various parts; the nucleus contains minute particles ... neutrons, and the atom's outer shell contains other particles called electrons. ... Physical Forms of Radiation; Radioactive Decay; Nuclear Fission; Ionizing Radiation ... of high-energy waves that can travel great distances at the speed of light and ...

Explanation:

The true statement of an alpha particle is it is an electron. The correct option is B.

The alpha particle are composite particles which consists of two protons and two neutrons tightly bonded together. They are ejected from the inside the nucleus of heavy radioactive particles, also called alpha decay.

Atoms are made up electrons orbiting in outer shells, protons and neutrons in the nucleus. The radioactive particle emit highly ionized radioactive rays which ionize electrons emitting alpha particle.

Thus, the correct option is B.

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Answer:

36.m/s/s

Explanation:

Answer:

Explanation:

(a) Force constant = force/displacement = 15/0.2

=75 N/m

(b) For SHM with spring, the angular frequency = sqrt ( force constant / mass )

= sqrt ( 75 / 1.8 )

= 6.455

Frequency = Angular frequency / 2pi

= 1.03Hz

(c) Maximum speed is when object's potential energy is at minimum.

1/2*mass*speed^2 = 1/2*force constant*displacement^2

speed^2 = 75*0.2^2/1.8 = 1.67

speed = sqrt (1.67)

= 1.29 m/s

(d) It occurs at x=0

(e) Maximum acceleration = Force / m = 15/1.8

= 8.33 m/s^2

(f) It occurs at x=0.2m

Answer:

Explanation:

given:

The mass of the object attached to the spring: m = 1.80 kg

The magnitude of the maximum horizontal force exerted: F = 15.0 N

The amplitude of the spring-object oscillation: A = 0.200 m

a. k=15/.2=75N/m

b. (2pi*frequency)^2 = k/m = 75/1.8 = 41.67

frequency = 1.03Hz

c. max speed^2 = amplitude^2*k/m = 0.2^2 * 41.67

max speed = 1.29 m/s

d. x=0m

e. max accel = F/m = 15/1.8 = 8.33 m/s^2

f. x=0.2m

e. energy = 1/2*k*A^2

= 1/2*75*0.2^2

= 1.5J

Answer:

B. Liquids

Explanation:

Just had this question on my test.

Hope this helps :)

Answer:

The speed of the student just before she lands, v₂ is approximately 8.225 m/s

Explanation:

The given parameters are;

The mass of the physic student, m = 43.0 kg

The height at which the student is standing, h = 12.0 m

The radius of the wheel, r = 0.300 m

The moment of inertia of the wheel, I = 9.60 kg·m²

The initial potential energy of the female student, P.E.₁ = m·g·h₁

Where;

m = 43.0 kg

g = The acceleration due to gravity ≈ 9.81 m/s²

h = 12.0 h

∴ P.E.₁ = 43 kg × 9.81 m/s² × 12.0 m = 5061.96 J

The kinetic rotational energy of the wheel and kinetic energy of the student supporting herself from the rope she grabs and steps off the roof, K₁, is given as follows;

[tex]K_1 = \dfrac{1}{2} \cdot m \cdot v_{1}^2+\dfrac{1}{2} \cdot I \cdot \omega_{1}^2[/tex]

The initial kinetic energy, 1/2·m·v₁² and the initial kinetic rotational energy, 1/2·m·ω₁² are 0

∴ K₁ = 0 + 0 = 0

The final potential energy of the student when lands. P.E.₂ = m·g·h₂ = 0

Where;

h₂ = 0 m

The final kinetic energy, K₂, of the wheel and student is give as follows;

[tex]K_2 = \dfrac{1}{2} \cdot m \cdot v_{2}^2+\dfrac{1}{2} \cdot I \cdot \omega_{2}^2[/tex]

Where;

v₂ = The speed of the student just before she lands

ω₂ = The angular velocity of the wheel just before she lands

By the conservation of energy, we have;

P.E.₁ + K₁ = P.E.₂ + K₂

∴ m·g·h₁ + [tex]\dfrac{1}{2} \cdot m \cdot v_{1}^2+\dfrac{1}{2} \cdot I \cdot \omega_{1}^2[/tex] = m·g·h₂ + [tex]\dfrac{1}{2} \cdot m \cdot v_{2}^2+\dfrac{1}{2} \cdot I \cdot \omega_{2}^2[/tex]

Where;

ω₂ = v₂/r

∴ 5061.96 J + 0 = 0 + [tex]\dfrac{1}{2} \times 43.0 \, kg \times v_{2}^2+\dfrac{1}{2} \times 9.60 \, kg\cdot m^2 \cdot \left (\dfrac{v_2}{0.300 \, m} }\right ) ^2[/tex]

5,061.96 J = 21.5 kg × v₂² + 53.[tex]\overline 3[/tex] kg × v₂² = 21.5 kg × v₂² + 160/3 kg × v₂²

v₂² = 5,061.96 J/(21.5 kg + 160/3 kg) ≈ 67.643118 m²/s²

v₂ ≈ √(67.643118 m²/s²) ≈ 8.22454363 m/s

The speed of the student just before she lands, v₂ ≈ 8.225 m/s.

Answer:

119 cm

Explanation:

Given heights :  200cm , 188 cm , 175 cm, 160 cm

since the eyes are at 95% level

95% of 200 cm = 190 cm

95% of 160 cm = 152 cm

hence the allowable height of mirror = 200 - ( 5 + 76 ) = 119 cm

and The mirror should be hung 75cm from the floor

Answer:

I have no idea.

Explanation:

I just wanted to tell you I absolutely read this wrong.

Answer:

Cornhole

Explanation:

Answer:

its D

Explanation:

i just got it correct on a. p. e. x. :)

Answer:

To stop a car must lose its momentum and its kinetic energy. ... If the forces on two cars are equal then the greater the kinetic energy the greater the distance before stopping. But there will be a relationship to the momentum because momentum and mass are both related to the kinetic energy.

Answer:

electrons move around nucleus in specific regions

We have that the correct statement that summarizes atoms over time will be

The discovery of new evidence resulted in changes to the atomic theory.

Option B

Generally

The Image shows that in the early 1800 the knowledge of atom was limited and it increased over time and by 1920 it had gone through a 4 stages of modifications to the atomic model

Therefore the correct statement that summarizes atoms over time will be

The discovery of new evidence resulted in changes to the atomic theory

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Answer:

Hello your question lacks some very vital information hence I will give you a general equation where you can input the missing values and get your answer

answer :  mass of Bananas ( m ) = [tex]\frac{A^2}{V^2} * K[/tex]

To calculate for weight of Bananas  = m * g      where g = 9.8

Explanation:

Given an amplitude ( A )= 29.8981

Spring constant = x ( unknown )

maximum speed of Bananas( v ) = wA  ( unknown )

question : calculate the weight of the bananas

First  step : calculate the period of oscillation

T = [tex]\frac{2\pi }{vA}[/tex] --- ( 1 )

next step : express T in terms of mass ( m ) of the bananas

= [tex]2\pi \sqrt{\frac{m}{k} } = \frac{2\pi }{vA}[/tex]

∴ m/k = A^2 / v^2

hence  mass of Bananas ( m ) = [tex]\frac{A^2}{V^2} * K[/tex]

To calculate for weight = m * g

Answer: [tex]18.22\ cm[/tex] from [tex]3.5\ nC[/tex] charge.

Explanation:

Given

The magnitude of the first charge is  [tex]Q_1=3.5\ nC[/tex]

The magnitude of the second charge is [tex]Q_2=5\ nC[/tex]

[tex]-6\ nC[/tex] charge must be placed in between the two charges to establish equilibrium

The electrostatic force is given by

[tex]F=\dfrac{kq_1q_2}{r^2}[/tex]

Equilibrium will be established when force by both the charges balance out each other. Suppose [tex]-6\ nC[/tex] is placed at a distance of [tex]x[/tex] cm from [tex]3.5\ nC[/tex] . So, we can write

[tex]\Rightarrow \dfrac{k(3.5)(-6)}{x^2}=\dfrac{k(5)(-6)}{(40-x)^2}[/tex]

Canceling similar terms

[tex]\Rightarrow \left [ \dfrac{40-x}{x}\right ]^2=\dfrac{10}{7}\\\\\Rightarrow \dfrac{40-x}{x}=\sqrt{\dfrac{10}{7}}=1.195\\\\\Rightarrow 40-x=1.195x\\\Rightarrow 40=2.195x\\\Rightarrow x=18.22\ cm[/tex]

Thus, the equilibrium position is [tex]18.22\ cm[/tex] from [tex]3.5\ nC[/tex] charge.

Answer:

What school do you go to?

Explanation: