A cave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. The lift is performed in three stages, each requiring a vertical distance of 15.0 m: (a) the initially stationary spelunker is accelerated to a speed of 2.40 m/s; (b) he is then lifted at the constant speed of 2.40 m/s; (c) finally he is decelerated to zero speed. How much work is done on the 85.0 kg rescue by the force lifting him during each stage

Answer:

Object C has the most potential energy.

Between A and B, we do not know which has more potential energy.

Explanation:

We know the object with the most potential energy and this is the object at C.

Potential energy is the energy due to the position of a body above the ground surface.

The higher a body is above ground, the more its potential energy.

 Potential energy  = mass x acceleration due to gravity x height

So;

 Object C has the most potential energy.

Between A and B, we do not know which has more potential energy.

This is because, the height and mass of the objects are not quantified using numbers.

Potential energy is a function of mass and height and acceleration due to gravity but acceleration due gravity is a constant.

Answer:

v = 6.79 m/s

Explanation:

It is given that,

Mass of a train car, m₁ = 11000 kg

Speed of train car, u₁ = 21 m/s

Mass of other train car, m₂ = 23000 kg

Initially, the other train car is at rest, u₂ = 0

It is a case based on inelastic collision as both car couples each other after the collision. The law of conservation of momentum satisied here. So,

\(m_1u_1+m_2u_2=(m_1+m_2)V\)

V is the common velocity after the collisions

\(V=\dfrac{m_1u_1}{(m_1+m_2)}\\\\V=\dfrac{11000\times 21}{(11000+23000)}\\\\V=6.79\ m/s\)

So, the two car train will move with a common velocity of 6.79 m/s.

1. The maximum height above its launch level is 1.45 m

2. The time of flight of the ball is 1.1 s

1. How do I determine the maximum height?

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

The maximum height can be obatianed as follow:

H = u²Sine²θ / 2g

H = [5.5² × (Sine 76)²] / (2 × 9.8)

Maximum height = 1.45 m

How do I determine the time of flight?

The time of flight of the ball can be obtained as follow:

T = 2uSineθ / g

T = [2 × 5.5 × Sine 76] / 9.8

Time of flight = 1.1 s

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The process of refraction of light​ occurs when light rays bends when travelling between media of different densities.

What is refraction of light?

Refraction of light is the bending of light rays or the change in the direction of light rays as it travels between media of different densities.

Light waves travel faster in media of less density than media of more density.

The change in density of the media makes light waves to be bend towards or away from the normal.

For example, when light travels from less dense air to more dense water, the light rays are bent towards the normal. However, when light rays travel from water to air, the light rays are refracted away from the normal.

In conclusion, refraction of light waves occur when light crosses the boundary of media of different densities.

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I suppose the hill makes an angle of 5.0° with the horizontal.

• F acts parallel to the road and in the direction of the car's motion, so it contributes a positive amount of work, F (290 m).

• Friction does negative work on the car since it opposes the car's motion. As the car moves up the slope, the work done by friction is (-524 N) (290 m) = -151,960 J.

• The car's weight has components that act parallel and perpendicular to the road. The parallel component has a magnitude of W sin(5.0°) and points down the slope, so it contributes negative work of -(1200 kg) g sin(5.0°) ≈ 1,024.95 J. The perpendicular component of W does not do any work.

• The normal force FN also doesn't do any work to move the car up the slope because it points perpendicular to the road, so we can ignore it, too.

The net work done on the car is then

F (290 m) + (-151,960 J) + 1,024.95 J = 150,000 J

==>   F (290 m) ≈ 300,935 J

==>   F ≈ (300,935 J) / (290 m) ≈ 1,037.71 N

Answer:

you can show them a vid

Explanation:

In your business plan, the target market section should clearly identify both your primary and secondary market(s). The market analysis is basically the target market section of your business plan. It is a thorough examination of the ideal people to whom you intend to sell your products or services.

This phenomenon is reflex action.

Reflex action is a surprising and involuntary response to stimuli. It helps organisms to quick adapt to an damaging condition that could have the potential to cause physical damage or maybe loss of life. Pulling our palms away right now after touching a hot or cold object is a traditional example of a reflex movement.

There are two reflexes, true reflexes, and bad reflexes. Proper reflexes assist with exercising, sports, and ordinary bodily activities such as driving, crossing the street, and working, however terrible reflexes can lead to damage and harm.

In a reflex action, the brain performs no element. The spinal cord, which reacts with out thinking about how to reply to stimuli, is in rate of those automated moves. It elicits no meaningful response inside the mind.

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Answer:

Option A. 4 m

Explanation:

Please see attached photo for diagram.

In the attached photo, X is the distance from the centre to which the student on the right must sit in order to balance the seesaw.

Clockwise moment = X × 45

Anticlock wise moment = 3 × 60

Clockwise moment = Anticlock wise moment

X × 45 = 3 × 60

X × 45 = 180

Divide both side by 45

X = 180 / 45

X = 4 m

Thus, the student must sit at 4 m from the centre.

The distance from the center the student on the right will be if they want the

seesaw to stay parallel to the ground is 4m

The question tells us that X is the distance to the center , each side of the

see saw is 5m with total length being 10m. This is explained in the

attached picture.

Clockwise moment = X × 45

Anticlock wise moment = 3 × 60

Clockwise moment = Anticlock wise moment

X × 45 = 3 × 60

X × 45 = 180

           = 180 / 45

            = 4m

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The pressure after the temperature has risen to 40.0 °C, assuming that there are no appreciable leaks or changes in volume is 4.35×10⁵ Pa

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

The pressure the temperature has risen to 40 °C can be obtained as follow:

P₁V₁ / T₁ = P₂V₂ / T₂

Volume = contant

P₁ / T₁ = P₂ / T₂

4.00×10⁵ / 288 = P₂ / 313

Cross multiply

P₂ × 288 = 4.00×10⁵ × 313

Divide both sides by 288

P₂ = (4.00×10⁵ × 313) / 288

P₂ = 4.35×10⁵ Pa

Thus, the pressure at 40 °C is 4.35×10⁵ Pa

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Answer: current is 3 A.

Explanation:

V = 6V

R = 2Ω

I = ?

∴ V = IR

I = V/R

I = 6V/2Ω

I = 6/2

I = 3 A ...answer...

hope that helps...

Answer:

3 amps

Explanation:

V = IR

V/R = I

6/2 = 3  amps

Answer:

The precision corresponds to the least count of the measurements, which is 0.1 cm 0.1 c m for the length of the box. In a similar manner, the precision of the volume is 0.01×103 cm3=10 cm3 0.01 × 10 3 c m 3 = 10 c m 3 .

Pipe of constant radius, we can use Bernoulli's equation, which relates the pressure, velocity, and height of a fluid at two points in a flow system.the pressure of water in the pipe is approximately 105,142 Pa.

System refers to a collection of related components or parts that work together to achieve a specific goal or purpose. The concept of a system can be applied to a wide range of fields and disciplines, including science, engineering, economics, and social sciences.

In science, a system is often defined as a portion of the universe that is being studied or analyzed. This can include anything from a single atom or molecule to an entire ecosystem or planet. By defining the boundaries of a system, scientists can focus their attention on understanding the interactions and relationships between the various components within that system.

In engineering, a system refers to a collection of components that are designed to work together to perform a specific function or task. This can include everything from simple mechanical systems like gears and pulleys to complex electrical or computer systems.

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Answer:

7000 meters

Explanation:

obviously 99.99 is less than 7000

10 cubed is 10 × 10 × 10, 1000, × 4.5 is 4500, which is less than 7000

10 squared is 100, which × 9 is only 900, which is also less than 7000

have a good day

a. The two cars are moving at the same speed at t = 3.88 seconds.

b. The two autos are moving at a speed of 4.18 cm/s at that moment.

c. The cars pass each other at time t = 1.05 s and t = 2.54 s, respectively.

d. At t = 1.05 seconds, the first car is located at 12.15 cm, and the second car is located at 16.55 cm. At t = 2.54 seconds, the first car is located at 10.69 cm, and the second car is located at 17.39 cm.

What is the speed of the two cars?

The speed of the cars is derived using the formula for linear velocity.

The velocity of the first car is calculated as follows:

v = v₀ + at

where;

The velocity of the second car can be calculated as:

v = v₀

where;

v₀ is the initial velocity since there is no acceleration.

We equate the two velocities of the two cars and solve for time:

-4.40 + 2.70t = 6.10

2.70t = 10.50

t = 3.88 seconds

b. To find the speeds of the cars at time t, we can substitute t = 3.88 seconds in the velocity equation for the first car:

For the first car:

v = -4.40 + 2.70 * 3.88

v = 4.18 cm/s

c. Solving for the time when the positions of the cars are equal allows us to determine when they pass one another.

The position of the first car will be:

x = x₀ + v₀t + 1/2 at²

where x₀ is the initial position.

The position of the second car will be:

x = x₀ + v₀t

equating the two positions equal and solving for time:

13.5 - 4.40t + 1/2 * 2.70t² = 10.5 + 6.10t

1.35t² + 1.70t + 3.00 = 0

Solving the quadratic equation, we get two times:

t = 1.05 s and t = 2.54 s

d. We can re-insert the time values into the position equation for each car to determine where the automobiles were at the times indicated in (c).

For t = 1.05 seconds:

First car:

x = 13.5 - 4.40 * 1.05 + 1/2 * 2.70 * 1.05²

x = 12.15 cm

Second car:

x = 10.5 + 6.10 * 1.05

x = 16.55 cm

For t = 2.54 seconds:

First car:

x = 13.5 - 4.40 * 2.54 + 1/2 * 2.70 * 2.54²

x = 10.69 cm

Second car:

x = 10.5 + 6.10 * 2.54

x = 17.39 cm

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The constant acceleration of the train is 0.33 m/s.

The average velocity can be calculated by using the formula:

velocity = distance/time

For the 1st car, the velocity is calculated as:

v₁ = 8.60 m / 1.80 s = 4.78 m / s

For the second car, velocity can be calculated as:

v₂ = 8.60 m / 1.66 s = 5.34 m / s

Now we can solve for the acceleration using the formula:

v₂² = v₁² + 2 a d

Rewriting in terms of a, we get

a = (v₂² – v₁²) / 2 d

a = (5.34)² – (4.78)² / (2 × 8.6)

a = 0.33 m/s

Therefore, the constant acceleration of the train is 0.33m/s.

what is acceleration explain?

acceleration, fee at which speed modifications with time, in terms of each pace and course. A factor or an object shifting in a directly line is improved if it hastens or slows down. motion on a circle is improved even if the velocity is steady, due to the fact the route is constantly converting

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Answer:

Ultraviolet rays from sun are very harmful from skin and can cause sunburn and skin diseases especially ultraviolet B rays. A sunscreen  lotion act as a protection barrier on the skin that restrict the direct contact of UV rays with skin and filter the harmful rays to enter the skin.

Radiotherapy is a medical therapy use to treat cancer. Radiotherapy commonly uses x-rays and gamma rays because they are high-energy particles or waves that kills or destroys the cancer cells.

Sunscreen lotion is able to filter this damaging ultraviolet radiation and prevent it from damaging the skin.

The sun reaches us from outer space brings ultraviolet rays to us. Ultraviolet rays are known to have some damaging effects on the skin. One way to protect our skin from this damaging ultraviolet rays is to use sunscreen lotion which is able to filter this damaging ultraviolet radiation and prevent it from damaging the skin.

X-rays and gamma rays are used in radiotherapy because they are light energy rays which are able to penetrate and destroy malignant cells in the body.

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Answer:

Iodine

Explanation:

fluorine is the most reactive

\({\mathfrak{\underline{\purple{\:\:\: Given:-\:\:\:}}}} \\ \\\)

\(\:\:\:\:\bullet\:\:\:\sf{Angle \ of \ projection = 30^{\circ} }\)

\(\:\:\:\:\bullet\:\:\:\sf{Initial \ velocity \ of \ projectile = 28 \: m/s^{-1} }\)

\(\\\)

\({\mathfrak{\underline{\purple{\:\:\:To \:Find:-\:\:\:}}}} \\ \\\)

\(\:\:\:\:\bullet\:\:\:\sf{Height_{\:(max)}\: reached\: by \:the \:projectile }\)

\(\\\)

\({\mathfrak{\underline{\purple{\:\:\: Calculation:-\:\:\:}}}} \\ \\\)

☯ As we know that,

\(\\\)

\(\dashrightarrow\:\: \sf{ H = \dfrac{u^2\;sin^2\theta}{2\;g} }\)

\(\\\)

\(\dashrightarrow\:\: \sf{H = \dfrac{(28)^2\;sin^2 30^{\circ}}{2\;(9.8)} }\)

\(\\\)

\(\dashrightarrow\:\: \sf{H = \dfrac{784 \times \;sin^230^{\circ}}{19.6} }\)

\(\\\)

\(\dashrightarrow\:\: \sf{ H = \dfrac{784}{19.6}\times sin^2 30^{\circ}}\)

\(\\\)

\(\dashrightarrow\:\: \sf{ H = \dfrac{784}{19.6}\times \bigg(\dfrac{1}{2}\bigg)^2 }\)

\(\\\)

\(\dashrightarrow\:\: \sf{ H = \dfrac{784}{19.6}\times \dfrac{1}{4} }\)

\(\\\)

\(\dashrightarrow\:\: {\boxed{\sf{H=10\:m }}}\)

The rms voltage measured across the secondary coil is 565.68 V.

The root mean square (RMS) value of an alternating current (AC) or voltage is the equivalent steady direct current (DC) value that produces the same heating effect or power dissipation in a resistor. In other words, it is the DC voltage or current that would produce the same amount of heat as the AC voltage or current over a given time period.

The rms voltage (V_rms) across the secondary coil can be calculated using the formula:

V_rms,secondary = (N_secondary/N_primary) * V_rms,primary

where N_secondary is the number of turns in the secondary coil, N_primary is the number of turns in the primary coil, and V_rms,primary is the rms voltage across the primary coil.

The rms voltage across the primary coil can be found from the given voltage function:

V_rms,primary = (1/√2) * V_peak,primary

where V_peak,primary = 200 V is the peak voltage across the primary coil.

Substituting the values, we get:

V_rms,primary = (1/√2) * 200 V = 141.42 V

Now, using the formula above, we can calculate the rms voltage across the secondary coil:

V_rms,secondary = (700/175) * 141.42 V = 565.68 V

Therefore, the rms voltage measured across the secondary coil is 565.68 V.

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It would take approximately 546 days for the decay rate of the sample of this radioactive isotope to fall to 0.58 of its initial rate.

1. The decay rate of a radioactive isotope is proportional to the number of radioactive atoms present in the sample at any given time.

2. The decay rate can be expressed as a function of time using the formula: R(t) = R₀ * \(e^{(-\lambda t\)), where R(t) is the decay rate at time t, R₀ is the initial decay rate, λ is the decay constant, and e is the base of the natural logarithm.

3. The half-life of a radioactive isotope is the time it takes for half of the radioactive atoms in a sample to decay. In this case, the half-life is given as 210 days.

4. Using the half-life, we can find the decay constant (λ) using the formula: λ = ln(2) / T₁/₂, where ln(2) is the natural logarithm of 2 and T₁/₂ is the half-life.

5. Substituting the given half-life into the formula, we have: λ = ln(2) / 210.

6. Now, we need to find the time it takes for the decay rate to fall to 0.58 of its initial rate. Let's call this time "t".

7. Using the formula for the decay rate, we can write: 0.58 * R₀ = R₀ * e^(-λt).

8. Simplifying the equation, we get: 0.58 = \(e^{(-\lambda t\)).

9. Taking the natural logarithm of both sides, we have: ln(0.58) = -λt.

10. Substituting the value of λ from step 5, we get: ln(0.58) = -(ln(2) / 210) * t.

11. Solving for t, we have: t = (ln(0.58) * 210) / ln(2).

12. Evaluating the expression, we find: t ≈ 546.

13. Therefore, it would take approximately 546 days for the decay rate of the sample of this radioactive isotope to fall to 0.58 of its initial rate.

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Answer:

Centripetal force is the force REQUIRED for circular motion. Centrifugal force is the force that makes something flee from the center.

Answer:

Halved

Explanation:

F=ma

Let case 1 (original) be:

\(F_{1}=m_{1} a_{1} \\\)

Case 2 (new) be:

\(F_{2}=m_{2} a_{2}\)

Mass is double:

\(m_{2}= 2m_{1}\)

Force kept the same:

\(F_{1} =F_{2}\)

Combine the equation and gives:

\(\frac{F_{1} }{F_{2}} =\frac{m_{1} a_{1} }{m_{2}a_{2} }\\\frac{F_{1} }{F_{1}} =\frac{m_{1} a_{1} }{2m_{1}a_{2} }\\1=\frac{a_{1} }{2a_{2} }\\a_{2}=\frac{1}{2} a_{1}\)

Acceleration is halved

Answer: you have to divide and multiple fam

Explanation:

The needle moves to one point and then  to another. Option C

A galvanometer is an instrument used for detecting and measuring small electric currents. It works based on the principle of the magnetic effect of an electric current.

The basic mechanism of a galvanometer involves a coil of wire suspended between the poles of a permanent magnet. When an electric current passes through the coil, it generates a magnetic field around it. The magnetic field interacts with the magnetic field of the permanent magnet, causing the coil to rotate.

A  galvanometer deflects due to the interaction between the magnetic field generated by the electric current passing through the coil and the magnetic field of the permanent magnet.

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Answer:

Minimum angular spread (in rad) = 547.45 x 10⁻⁶ rad

Explanation:

GIven;

Wavelength of manganese vapor laser beam = 534 nm = 534 x 10⁻⁹ m

Diameter =  1.19 mm = 1.19 x 10⁻³ m

Find:

Minimum angular spread (in rad)

Computation:

Minimum angular spread (in rad) = 1.22[Wavelength / Diameter]

Minimum angular spread (in rad) = 1.222[(534 x 10⁻⁹) / (1.19 x 10⁻³)]

Minimum angular spread (in rad) = 2[448.73 x 10⁻⁶]

Minimum angular spread (in rad) = 547.45 x 10⁻⁶ rad

Answer:

The speed of the object is (\(3i - 4.00tj\))m/s

The magnitude of the acceleration is 4.00m/s²

Explanation:

Given - position vector;

r = (2.0 + 3.00t)i + (3.0 - 2.00t²)j       -------------------(i)

To get the speed vector (\(v\)), take the first derivative of equation (i) with respect to time t as follows;

\(v\) = \(\frac{dr}{dt}\)

 \(v\) = \(\frac{d[(2.0 + 3.00t)i + (3.0 - 2.00t^2)j] }{dt}\)  

\(v\)  = \(3i - 4.00tj\)      ------------------------(ii)

To get the acceleration vector (\(a\)), take the first derivative of the speed vector in equation(ii) as follows;

\(a = \frac{dv}{dt}\)

\(a = \frac{d(3i - 4.00tj)}{dt}\)

\(a = -4.00\)j

The magnitude of the acceleration |a| is therefore given by

|a| = |-4.00|

|a| = 4.00 m/s²

In conclusion;

the speed of the object is (\(3i - 4.00tj\))m/s

the magnitude of the acceleration is 4.00m/s²

The force on the Moon is about 3.4 times less than the force on Earth.

The gravitational force experienced by an object with mass m due to the gravitational attraction of a celestial body with mass M and radius R is given by the formula:

F = G * (m * M) / R^2

where G is the gravitational constant, which is approximately equal to 6.67 × 10^-11 N m^2/kg^2.

For the 35 kg mass at the surface of the Earth, the force would be:

F = G * (m * M) / R^2

F = 6.67 × 10^-11 N m^2/kg^2 * (35 kg * 6 * 10^24 kg) / (6.4 * 10^6 m)^2

F = 274.2 N

For the Moon with mass 81.3 times that of the Earth and a radius of 0.27 times that of the Earth, the force on an object with a mass of 35 kg would be:

F = G * (m * M) / R^2

F = 6.67 × 10^-11 N m^2/kg^2 * (35 kg * 81.3 * 6 * 10^24 kg) / (0.27 * 6.4 * 10^6 m)^2

F = 924.6 N

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