Question 4: Scientists and engineers often plan investigations to see how changing one variable affects the outcome. A variable is any trait, condition or feature of something being tested. Imagine a team is testing the speed of a toy car. In trial 1, they test the car and measure how long it takes it to travel 2 meters. In trial 2, they want to investigate how changing a variable affects the car's speed. Which of the following plans is BEST for trial 2?

Answer: C) the thickness of a sheet of paper.

Explanation:

A micrometer screw gauge is a tool that measures distances (in order of millimeters), from this, we can see that the correct option is C: the thickness of a sheet of paper.

Now let's expand on this.

Knowing that the micrometer only can measure distances, we need to analyze which of the options is only a distance.

Notice that while area and volume have similar units, are really different things.

So analyzing the options we have:

A) "the area of a sheet of paper"

To find the area we need two measures (length and width) and then multiply this, but with a micrometer, we never measure the length of a sheet of paper (the maximum measure that you can get in a micrometer is of a few centimeters).

B) "the mass of a sheet of paper"

We can't measure mass with a micrometer.

C) " the thickness of a sheet of paper"

The thickness of a sheet of paper is of the order of 1mm, so we can easily measure this with a micrometer screw gauge.

D) " the volume of a sheet of paper​"

We have a similar problem as the one seen in A.

Then the correct option is C.

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Answer:

60×60×24=86,400

Explanation:

i.e. 86,400 secs is 1 day

1 hour = 60 minutes

1 minute = 60 seconds

1 day = 24 hours

60 min. × 60 sec. × 24 hr.

60 × 60 × 24 = 86,400 seconds

∴ 86,400 seconds = 1 day

It’s 180 m/s^2 dude. I think I have you in my class lol.

The centripetal acceleration of an object is due to the changing velocity in a circular path and the centripetal acceleration of the bicycle is 182.85 m/s².

Centripetal acceleration of an object can be defined as the property of the motion of an object which is traversing a circular path. Any object which is moving in a circular path and has an acceleration vector pointed towards the center of that circular path is known as Centripetal acceleration.

The centripetal acceleration of an object can be calculated by the formula:

ac = v²/ r

where, ac = centripetal acceleration,

v = velocity of the object,

r = radius of the circular path

The centripetal acceleration of the object will be:

ac = (8)²/ r

radius = diameter/ 2

radius = 70/ 2

radius = 35cm or 0.35 m

ac = 64/ 0.35

ac = 182.85 m/s²

Therefore, the centripetal acceleration of the bicycle will be 182.85 m/s².

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This is because of continuous usage, the wire loses its elasticity and dose not regain it original dimension

Answer:

When a spring balance has been used for a long time, the spring in the balance fatigued and there is loss of strength of the spring. In such a case, the extension in the spring is more for a given load and hence the balance gives wrong readings.

Answer:

13.759 % of the initial mechanical energy is lost as thermal energy.

Explanation:

By the First Law of Thermodynamics we know that increase in internal energy of the object ([tex]U[/tex]), in joules, is equal to the lost amount of the change in gravitational potential energy ([tex]U_{g}[/tex]), in joules:

[tex]\frac{x}{100} \cdot \Delta U_{g} = \Delta U[/tex] (1)

Where [tex]x[/tex] is the percentage of the energy loss, no unit.

By definition of the gravitational potential energy and internal energy, we expand this equation:

[tex]\frac{x\cdot m \cdot g \cdot h}{100} = m\cdot c\cdot \Delta T[/tex] (1b)

Where:

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

[tex]g[/tex] - Gravitational acceleration, in meters per square second.

[tex]h[/tex] - Initial height of the object above the lunar ground, in meters.

[tex]c[/tex] - Specific heat of aluminium, in joules per degree Celsius-kilogram.

[tex]\Delta T[/tex] - Temperature increase due to collision, in degree Celsius.

If we know that [tex]m = 0.95\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]h = 75\,m[/tex], [tex]c = 920\,\frac{J}{kg\cdot ^{\circ}C}[/tex] and [tex]\Delta T = 0.11\,^{\circ}C[/tex], then the percentage of energy loss due to collision is:

[tex]x = \frac{100\cdot c\cdot \Delta T}{g\cdot h}[/tex]

[tex]x = \frac{100\cdot \left(920\,\frac{J}{kg\cdot ^{\circ}C} \right)\cdot (0.11\,^{\circ}C)}{\left(9.807\,\frac{m}{s^{2}} \right)\cdot (75\,m)}[/tex]

[tex]x = 13.759\,\%[/tex]

13.759 % of the initial mechanical energy is lost as thermal energy.

Answer:

Resultant force is 20 N

Explanation:

Resolving vertically:

[tex]{ \sf{F_{y} = (8 \cos 30 \degree) + (12 \cos 30 \degree) }} \\ { \sf{ \sum F_{y} = 17.3 \: newtons }}[/tex]

Resolving horizontally:

[tex]{ \sf{F_{x} = (8 \sin 30 \degree) + (12 \sin 30 \degree) }} \\ { \sf{ \sum F _{x} = 10 \: newtons}}[/tex]

Resultant force:

[tex]{ \boxed{ \bf{F = \sqrt{ {F _{x} }^{2} + {F _{y} }^{2} } }}} \\ { \sf{F = \sqrt{ {17.3}^{2} + {10}^{2} } }} \\ { \sf{F = \sqrt{399.29} }} \\ F = 19.98 \approx20 \: newtons[/tex]

Answer:

Move. It also determines the total amount of force put on an object

Explanation:

The question is incomplete, the complete question is;

The net force determines how and if an object will?

A) make a balanced force

B) change its mass

C) move or accelerate

When unbalanced forces act on an  object, the object moves  or accelerates. The correct answer is option C: move or accelerate

Force is considered as a push or pull. Unbalanced forces refers to a system of forces acting in opposite direction and are not equal in magnitude.

Unbalanced forces cause an object to move or accelerate in the direction of the larger force.

Hence, The net or resultant force determines how and if an object will move or accelerate when under the action of unbalanced forces.

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Answer:

Efficiency of a machine is 90% this means that the total energy produced to the machine only 90% is useful and given as a output.

Machines are not 100% efficient because some of the work done by a machine is used to overcome friction

Answer:

why is fraction called a necessary evil

The heat for a temperature in plastic increases at the range of 50°C to 100°C then the plastic decreases its stiffness or flexural modulus.

It is given that the temperature is increased from 50°C to 100°C that means temperature is increasing.

It is required to state the effect of increase in heat on plastic.

The plastic starts to lose its stiffness or we say that it converts into a softened material as long as we increase the temperature of the material.

So if we increase the temperature too much or exceed above the limit of temperature range then it will distort.

Also there are many qualities that can be affected by increasing the temperature like mechanical property, material fatigue or chemical phenomenon.

Therefore, the heat for a temperature range of 50°C to 100°C

Plastic increases then the plastic decreases its stiffness or flexural modulus.

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Answer:

16.50 m/s²

Explanation:

initial velocity(u)=45.2 m/s

final velocity(v)= 0 (it stops)

time taken(t)= 2.74 s

now,we have

acceleration(a)= (v-u)/t

= (0-45.2 m/s)/2.74s

= -45.2 m/s / 2.74s

= -16.50 m/s²

Answer:

[tex]\boxed {\boxed {\sf -16.5 \ m/s^2}}[/tex]

Explanation:

We are asked to find the acceleration of a man driving. Acceleration is the change in velocity over the change in time. Acceleration is calculated with the following formula.

[tex]a= \frac{v_f- v_i}{t}[/tex]

The driver's initial velocity is 45.2 meters per second. His final velocity is 0 meters per second because he came to a stop. He stopped in 2.74 seconds.

[tex]\bullet \ v_f= 0 \ m/s \\\bullet \ v_i= 45.2 \ m/s \\\bullet \ t= 2.74 \ s[/tex]

Substitute these values into the formula.

[tex]a= \frac{0 \ m/s - 45.2 \ m/s }{ 2.74 \ s}[/tex]

Solve the numerator by subtracting.

[tex]a= \frac{- 45.2 \ m/s }{ 2.74 \ s}[/tex]

[tex]a= -16.49635036 \ m/s^2[/tex]

The original measurements of velocity and time have 3 significant figures, so our answer must have the same. For the number we calculated, that is the tenths place. The 9 in the hundredth place tells us to round the 4 in the tenths place up to a 5.

[tex]a \approx -16.5 \ m/s^2[/tex]

The acceleration is approximately -16.5 meters per second squared. The acceleration is negative because the man slowed down and came to a stop.

Answer:

Work, in physics, measure of energy transfer that occurs when an object is moved over a distance by an external force at least part of which is applied in the direction of the displacement. ... To express this concept mathematically, the work W is equal to the force f times the distance d, or W = fd.

Answer:

10 x 10⁴

I hope it's helps you

Answer:

Yes

Explanation:

Explanation:

a) copper

b) olive oil

Hope it helps✌✌

Gamma rays

used in radiotherapy

Answer:

.21

Explanation:

i see everyone got it wrong so ill give you the answer, good luck :)

Answer:

similar type of electric charges attract one another

I think this is a coorect staement

Answer:

C ) An electroscope is used to determine the presence of electrostatic charges

Answer:

A turndra B rainforest

Explanation:

Answer:

v = 2.85 m/s

Explanation:

Given that,

A skipper on a boat notices wave crests passing his anchor chain every 5.6 s.

The distance between wave crests to be 16 m.

We need to find the speed of the waves. The speed of a wave can be calculated by the formula as follows :

[tex]v=f\lambda\\\\v=\dfrac{\lambda}{T}\\\\v=\dfrac{16}{5.6}\\\\v=2.85\ m/s[/tex]

So, the speed of the wave is 2.85 m/s.

Answer: The mass of copper liberated is 0.196 g.

Explanation:

The oxidation half-reaction of copper follows:

[tex]Cu\rightarrow Cu^{2+}+2e^-[/tex]

Calculating the theoretical mass deposited by using Faraday's law, which is:

[tex]m=\frac{M\times I\times t(s)}{n\times F}[/tex] ......(1)

where,

m = actual mass deposited = ? g

M = molar mass of metal = 63 g/mol

I = average current = 2 A

t = time period in seconds = 5 min = 300 s (Conversion factor: 1 min = 60 sec)

n = number of electrons exchanged = 2

F = Faraday's constant = 96500 C/mol

Putting values in equation 1, we get:

[tex]m=\frac{63 g/mol\times 2A\times 300s}{2\times 96500 C/mol}\\\\m=0.196g[/tex]

Hence, the mass of copper liberated is 0.196 g.

Answer:

Momentum of system = 37.2 Kgm/s.

Explanation:

Given the following data;

To find the momentum of the system;

Momentum can be defined as the multiplication (product) of the mass possessed by an object and its velocity. Momentum is considered to be a vector quantity because it has both magnitude and direction.

Mathematically, momentum is given by the formula;

Momentum = mass * velocity

For object A;

Momentum A = 5 * 6

Momentum A = 30 Kgm/s

For object B;

Momentum B = 12 * 0.6

Momentum B = 7.2 Kgm/s

Next, we would determine the momentum of this system using the formula;

Momentum of system = Momentum A + Momentum B

Substituting the values into the formula, we have;

Momentum of system = 30 + 7.2

Momentum of system = 37.2 Kgm/s.

Answer:

By studying.

By paying attention to what the teacher is saying.

That's the way to receive knowledge.

HAVE A GREAT DAY

Explanation:

Please give me that little crown...

AND REMEMBER TO SMILE

Answer:

Distance cover in 2  hour = 6 kilometer

Explanation:

Given equation:

x = 2t - 10

where

x = kilometer

t = hour

Find:

Distance cover in 2  hour

Computation:

T = 2

So,

x = 2t - 10

x = 2(2) - 10

x = 4 - 10

x = -6

Distance cover in 2  hour = 6 kilometer

Answer:

The distance is 6 km.

Explanation:

The equation of uniform linear motion of a particle has the form: x = 2t – 10. (x: km, t: h). What is the distance traveled by the particle after 2 hours?

x = 2t - 10

distance traveled after t = 2 hours

Substitute t = 2 in the given expression

x = 2 x 2 - 10

x = 4 - 10

x = - 6 km

So, the distance is 6 km.

Answer:

A derived unit is a SI unit of measurement comprised of a combination of the seven base units. Like SI unit of force is the derived unit, newton or N where N=s21×m×kg. There are some commonly used derived units which includes: 1. Pressure = AreaForce=m2N.

Explanation:

Answer:

A body having uniform velocity has zero acceleration because

there is not change in velocity.

THIS IS YOUR ANSWER :

Archimedes’ principle, physical law of buoyancy, discovered by the ancient Greek mathematician and inventor Archimedes, stating that any body completely or partially submerged in a fluid (gas or liquid) at rest is acted upon by an upward, or buoyant, force, the magnitude of which is equal to the weight of the fluid displaced by the body.

☺✍️HOPE IT HELPS YOU ✍️☺

Explanation:

The derivative of a constant term is always 0. So the acceleration of the body would be zero. Hence, the acceleration of a body moving with uniform velocity will always be zero.

hope it helps you

Answer:

a)  [tex]h=25m[/tex]

b)  [tex]v=19.8m/sec[/tex]

Explanation:

From the question we are told that:

Height [tex]h=25m[/tex]

Bounce Height [tex]h'=20m[/tex]

Generally the Kinematic equation is mathematically given by

[tex]V=\sqrt{2gh}\\\\V=\sqrt{2*9.81*25}[/tex]

[tex]V=22.1m/sec[/tex]

Therefore Height

[tex]h=\frac{V^2}{2g}\\\\h=\frac{22.1^2}{2*9.81}[/tex]

[tex]h=25m[/tex]

b)

Generally the Kinematic equation is mathematically given by

[tex]v^2=2ah[/tex]

[tex]v^2=2*9.8*20[/tex]

[tex]v=\sqrt{2*9.8*20}[/tex]

[tex]v=19.8m/sec[/tex]

Answer:

It is already balanced

Explanation:

It is already balanced

Explanation:

because the moon has less mass than earth, the force due to gravity at the lunar surface is only about 1/6 that on earthso,the weight of a body on earth is 6×5N =30N