Grade 8 Science Admin. May 2018 Released
37 A physics teacher performed a demonstration for a science class by pulling a crate across the
floor and measuring the force with a spring scale. While she pulled, a student measured the
acceleration of the crate with a handheld electronic device. The results of three trials are
shown below
Motion
F = 900 N
Actual Acceleration
of Crate
Trial
1
140 kg
Acceleration
(m/s)
0.36
0.34
0.38
0.36
2
3
Average
The teacher asked the class to calculate the acceleration of the crate based on the crate's
mass and the force she applied. What conclusion can be made about the difference between
the calculated acceleration and the actual acceleration that occurred in the trials?
A Another force in the direction of the motion produced a lower acceleration than calculated.
B An opposing force caused by friction produced a lower acceleration than calculated.
C Another force in the direction of the motion produced a higher acceleration than
calculated.
D An opposing force caused by friction produced a higher acceleration than calculated,

The potential difference Vab remains unchanged. Since the potential difference across the 4V battery is now 17V, the potential difference across the 12V battery is still 12V.  The potential difference is still 4V.

Given the initial emf of circuit (V1) =4V

The battery is increased to (V2) = 17V

According to the Kirchhoff loop rule, the total current flowing into and out of a junction must equal one another. In other words, the sum is equal to zero. Using equation 1 and the Kirchhoff loop rule, we can calculate Vab (the voltage across ab) when the external magnetic field is 12 volts.

+12 - (I x 2) -(I x 3)-(I x 4)-(4)-(I x 7) = 0

I = 8/16 = 0.5 A

Vab = 4V + (I x 7) + (I x 4)

Vab = 4V + (0.5 x 7) + (0.5 x 4) = 4 +3.5+2 = 9.5 V

Using equation 1 and the Kirchhoff loop rule, we can calculate Vab (the voltage across ab) when the external magnetic field is 17 volts.

+17 - (I x 4) -(I x 3)-(I x 2)-(12)-(I x 7) = 0

I = 5/16 = 0.3125A

Vab = 17V -(I x 7) - (I x 4)

Vab = 17 - ( 0.3125 x 4)-(0.3125  x 7) = 17 - 1.25 - 2.1875 = 13.5625V

To learn more about potential difference click here https://brainly.com/question/12198573

#SPJ4

The magnitude of the displacement vector of the bee will be 2 km. Because the distance between the endpoints is 2km.

A displacement is a vector in engineering and mechanics that has a length equal to the smallest distance between a point P's initial and final positions. It is a vector quantity. The SI unit of the displacement is the meter.

A honeybee leaves the hive and travels a total distance of 2 km before returning to the hive.

The bee's displacement vector will be 2 kilometers in length. Mostly due to the 2 kilometers between the terminals.

More about the displacement link is given below.

https://brainly.com/question/11934397

#SPJ4

Answer:

Table Salt

Explanation:

Table Salt has free ions in water that conduct electricity so when mixed with water produces the best conductance of electricity

Answer:

d q=3 m/s

Explanation:

im not too sure hope that helps

The correct answer is not provided in the given options A, B, C, or D. The distance from the axis at which the magnetic field caused by the current is equal in magnitude to Earth's magnetic field is 125 meters.

To find the distance from the conductor at which the magnetic field caused by the current is equal to the Earth's magnetic field, we'll use the formula for the magnetic field around a long straight conductor:

\(B = (de * I) / (2 * \pi  * r)\)

Where B is the magnetic field, μ₀ is the permeability of free space (\(4\pi  * 10^-7 Tm/A\)), I is the current, and r is the distance from the conductor. We want to find the value of r when B equals Earth's magnetic field (0.5 x 10⁻⁴ T).

\(0.5 * 10^-4 T = (4\pi  * 10^-7 Tm/A * 100 A) / (2 * \pi  * r)\)
To solve for r, we can first simplify the equation by cancelling the π terms:

\(0.5 * 10^-4 T = (4 * 10^-7 Tm/A * 100 A) / (2 * r)\)

Now, cancel out the A (Amperes) terms:

\(0.5 * 10^-4 T = (4 * 10^-7 Tm) / (2 * r)\)

Divide both sides by 4 x 10⁻⁷ T:

\(r = (0.5 * 10^-4 T) / (4 * 10^-7 T)\)

Simplify the equation:

r = \(0.5 * 10^3 m / 4\)
r = 500 / 4
r = 125

So, the correct answer is not provided in the given options A, B, C, or D. The distance from the axis at which the magnetic field caused by the current is equal in magnitude to Earth's magnetic field is 125 meters.

Learn more about magnetic field here:

https://brainly.com/question/31083597

#SPJ11

Answer:

I would say tension force the last one because the gravitational force brinsg it down more.

Explanation:

Dont mind if its wrong im sorry

Answer:

15000000 m

Explanation:

From the question,

Speed (S) = Distance(d)/Time(t)

S = d/t....................... Equation 1

Make d the subject of the equation

d = St..................... Equation 2

Given: S = 50 km/s = 50000 m/s, t = 5 minutes = 5*60 seconds = 300 seconds

Substitute these values into equation 2

d = 50000(300)

d = 15000000 m

Hence the skier travels 15000000 m

Given:

The initial height of the ball, h=1.6 m

The initial speed of the ball, u=14 m/s

To find:

a) The time of flight of the ball.

b) The range of the ball.

Explanation:

As the ball is thrown horizontally, the ball will have no vertical component of the initial velocity. The velocity of the ball is completely horizontal.

Thus the vertical component of the initial velocity of the ball is u_y=0 m/s.

The horizontal component of the initial velocity of the ball is u_x=u=14 m/s.

a)

From the equation of motion,

Where g is the acceleration due to gravity and t is the time of flight of the ball.

On substituting the known values,

b)

The range of the ball is given by,

On substituting the known values,

Final answer:

a) The time of flight of the ball is 0.57 s

b) The range of the ball is 7.98 m

The spilled volume of water from the open cylindrical tank, when rotated at 90 rpm, is approximately 0.095 cubic meters.

When the cylindrical tank is rotated, the water inside experiences centrifugal force. This force pushes the water towards the outer edges of the tank, causing it to rise and potentially spill over. To determine the spilled volume, we need to calculate the difference in height between the water level at rest and the water level when the tank is rotating at 90 rpm.

First, we calculate the circumference of the tank using the formula: circumference = 2πr, where r is the radius. Plugging in the given radius of 0.30 meters, we get a circumference of approximately 1.89 meters.

Next, we need to determine the distance traveled by a point on the water's surface when the tank completes one revolution at 90 rpm. To do this, we use the formula: distance = (circumference × rpm) / 60. Substituting the values, we find the distance traveled per minute is approximately 2.98 meters.

Since the tank has a height of 1.2 meters, the ratio of the distance traveled to the tank height is approximately 2.48. This means that the water level will rise by 2.48 times the height of the tank when rotating at 90 rpm.

Finally, we calculate the spilled volume by subtracting the initial height of the water from the increased height. The spilled volume is given by the formula: volume = πr^2(h_new - h_initial), where r is the radius and h_new and h_initial are the new and initial heights of the water, respectively.

Plugging in the values, we get: volume = π(0.3^2)(1.2 × 2.48 - 1.2) ≈ 0.095 cubic meters.Therefore, the spilled volume of water is approximately 0.095 cubic meters.

Learn more about spilled volume

brainly.com/question/11799197

#SPJ11

²

tail rail holds the towel from a certain way where the water climbs down

Answer:

12113.318mL

Explanation:

I hope this helps

Explanation:

the answer is in the above image

Given:

mass of first ball, m1 = 35g

mass of second ball, m2 = 75g

velocity of first ball before collision, u1 = 9m/s

velocity of second ball before collision, u2 = -7m/s

velocity of first ball after collision, v1 = -15m/s

velocity of second ball after collision, v2 = ? (To Find)

Now it is given that there is no net force on the system of two balls

according to the Law of Conservation of Momentum so, here momentum is constant before and after collision:

P1 = P2

m1u1 + m2u2 = m1v1 + m2v2

35g*9m/s + 75g*(-7m/s) = 35g*(-15m/s) + 75g*v2

v2 = (35g*9m/s + 75g*(-7m/s) - 35g*(-15m/s))/75g

v2 = 4.2m/s

therefore, the velocity of second ball after collision is 4.2m/s

As a result, the equation of the law of conservation of momentum is as follows: m1 u1 + m2 u2 represents the total momentum of particles A and B before the collision, and m1 v1 + m2 v2 represents the total momentum of particles A and B after the collision.

Momentum. If the mass of an object is m and it has a velocity v, then the momentum of the object is defined to be its mass multiplied by its velocity. momentum = mv. Momentum has both magnitude and direction and thus is a vector quantity. The units of momentum are kg m s−1 or newton seconds, N s.

Learn more about Law of Conservation of Momentum here

https://brainly.com/question/7538238

#SPJ2

Without:

With safety:

Answer:

Explanation:

Films are widely popular and their audio visual nature provides them a pervasive power for social influence. Therefore, they have the potential to play an important role as a medium of entertainment, information and education and as a catalyst for social change. Films are popular because they entertain.

Movies are about sitting in a theatre, watching something- watching a story unfold with people you don't know- watching that happen and emoting an emotion knowing that for those two hours or so, when one walks into that theatre, he/she don't have to worry about what is going on outside.

Answer:

area is called scalar quantity because there is no need of direction to define and also follow the algebric summation ..... is your answer

1 ft²= 0.09290304m²

so:

43560ft²= 0.09290304m²×43560

= 4,046.8564224 m²

Answer: 4046.9m² (approx.)

Explanation:

An acre is 43560 ft², but the US has two feet, the International foot, and the (old) Survey foot. Since 1983, the answer varies by state according to which foot the State has adopted for surveying. (Previously, it was always the Survey foot).

International: 43560 ft² x (0.3048 m/ft)² = 4046.856 422 m²

Survey: 43560 ft² x (1200/3937 m)² = 4046.872 610 m²

Both round to 4046.9 m² if that’s good enough, but there is a tiny difference.

To know more about conversions, refer to:

Reference link - https://brainly.com/question/1462592

#SPJ2

The distance between the two planes after 2 hours is approximately 1288.94 miles.

Given, One plane flies at 20 degrees east of north at 500 miles per hour

The second plane flies at 30 degrees east of south at 600 miles per hour.

Using Pythagorean theorem, D = √((500 * cos 20 * 2)^2 + (500 * sin 20 * 2 + 600 * sin 30 * 2)^2)On calculating, we get:D ≈ 1288.94 miles

Hence, the distance between the two planes after 2 hours is approximately 1288.94 miles. Hence, the detail ans is as follows:

Given, One plane flies at 20 degrees east of north at 500 miles per hour.The second plane flies at 30 degrees east of south at 600 miles per hour.

To find: The distance between the two planes after 2 hours. We can solve this problem by using the Pythagorean theorem.

Let's suppose the initial position of both the planes is 'O' and after 2 hours they are at positions 'P' and 'Q' as shown in the figure below. The distance between the two planes is PQ.

Using Pythagorean theorem, we get:D = √((500 * cos 20 * 2)^2 + (500 * sin 20 * 2 + 600 * sin 30 * 2)^2)On calculating, we get:D ≈ 1288.94 miles

Hence, the distance between the two planes after 2 hours is approximately 1288.94 miles.

Learn more about distance

brainly.com/question/13034462

#SPJ11

If both masses double in size and their separation between them triples. 13..33 N will be the force between the masses.

Newton's law of gravity states that each particle having mass in the universe attracts each other particle with a force known as the gravitational force.

Gravitational force is proportional to the product of the masses of the two bodies and inversely proportional to the square of their distance.

Given data:

The gravitational force = 30 N

Mass 1 =m₁

Mass 2=m₂

Distance between charges = R

Condition given:

Mass 1 = 2m₁

Mass 2= 2m₂

Distance  between charges = 3R

\(\rm F = \frac{Gm_1m_2}{R^2}\)

Case 2;

\(\rm F'=\frac{G(2m_1)(2m_2)}{(3R)^2} \\\\ F'=\frac{4}{9} \frac{Gm_1m_2}{R^2} \\\\ F'=\frac{4}{9} F \\\\ F'=\frac{4}{9} \times 30 \\\\ F'=13.33 \ N\)

Hence, the forces between the masses will be 13..33 N.

To learn more about the gravitational force refer to the link;

https://brainly.com/question/24783651

#SPJ1

All the options given should be part of solving any problem in physics.

Physics problem-solving calls for a methodical and meticulous approach. First and foremost, it's critical to attentively analyze the problem and comprehend the condition presented.

A situational drawing might aid in visualizing the issue and highlighting any crucial elements. Next, it's important to note down each and every variable that the problem provides. The next step is to consider whether physics concepts are applicable to the issue and choose the appropriate equations to apply them.

Once the calculation has been completed, it is crucial to double-check the answer's units to make sure they are formatted correctly. Finally, evaluate the reasonableness of your response and make any required modifications.

To know more about physics here:

https://brainly.com/question/28600368

#SPJ4

Answer:

Explanation:

No, not any of these substance will float in Methanol , simply because Methanol has a density of 0.79 g, if you put any substance that weighs more than 0.79 g, it will sink, it all depends on the weight if it is more or less than methanol  

2: D=m/v

D=135/50 = 2.7 g/cm³ ( Aluminum)

D=M/V

if two objects has the same mass but one has larger volume, then te one with larger volume has less density

example : 2 objects

mass of both=350

volume of the first one=500 and  the other 750

D1=M1/V1 = 350/500 =0.7

D2 = M2/V2 = 350/750 = 0.4666

D1 is larger than D2( with larger volume )

About 1,360 watts per square meter

At Earth's average distance from the Sun (about 150 million kilometers), the average intensity of solar energy reaching the top of the atmosphere directly facing the Sun is about 1,360 watts per square meter, according to measurements made by the most recent NASA satellite missions.

Answer:

m = 15 kg

Explanation:

Applied force to the cart, F' = 18 N

Force of friction, f = 15 N

Net force acting on the cart,

F = F' - f

F = 18 - 15

F = 3 N

The change in velocity of the cart is 1 m/s every 5 s.

We need to find the mass of the cart.

The formula of net force is given by :

F = ma, where a is the acceleration of the cart

\(F=\dfrac{m\Delta v}{t}\\\\m=\dfrac{Ft}{\Delta v}\\\\m=\dfrac{3\times 5}{1}\\\\m=15\ kg\)

So, the cart's mass is 15 kg.

Answer:

A switch interrupts the flow of current in a circuit.

Explanation:

Answer:

The answers to your questions are given below

Explanation:

A. Definition of momentum.

Momentum of an object can be defined as the product of the mass of the object and its velocity. Mathematically, it expreessed as:

Momentum = mass x Velocity

From the above equation, we can derive the SI unit of momentum as follow:

Mass is measured in Kilogram (Kg)

Velocity is measured in meter per second (ms¯¹).

Momentum = mass x Velocity

Momentum = Kg x ms¯¹

Momentum = Kg•ms¯¹

Therefore, the SI unit of momentum is Kg•ms¯¹.

Bi. Determination of the force of the body from O to A.

Mass (m) = 5 kg

Velocity (v) = 40 ms¯¹

Time (t) = 2 secs.

Force (F) =?

Next, we shall determine the acceleration of the body.

Acceleration (a) = Velocity (v) /Time (t)

a = v /t

Velocity (v) = 40 ms¯¹

Time (t) = 2 secs.

Acceleration (a) =.?

a = v/t

a = 40/2

a = 20 ms¯²

Now, we can obtain the force as follow:

Mass (m) = 5 kg

Acceleration (a) = 20 ms¯²

Force (F) =?

Force (F) = mass (m) x Acceleration (a)

F = ma

F = 5 x 20

F = 100 N

Therefore, the force of the body from O to A is 100 N.

Bii. Determination of the force of the body from B to C.

Mass (m) = 5 kg

Velocity (v) = 40 ms¯¹

Time (t) = 10 – 6 = 4 secs.

Force (F) =?

Next, we shall determine the acceleration of the body.

Acceleration (a) = Velocity (v) /Time (t)

a = v /t

Velocity (v) = 40 ms¯¹

Time (t) = 4 secs.

Acceleration (a) =.?

a = v/t

a = 40/4

a = 10 ms¯²

Now, we can obtain the force as follow:

Mass (m) = 5 kg

Acceleration (a) = 10 ms¯²

Force (F) =?

Force (F) = mass (m) x Acceleration (a)

F = ma

F = 5 x 10

F = 50 N

Therefore, the force of the body from B to C is 50 N.

he was the first day at the end

Answer:

ν=293.53 Hz

Explanation:

ν= speed/λ

speed = 204 m/s

λ=0.695 m

v = 204 m/s * 1/0.695m

meters cancels out

1/s = Hz

v = 204/0.695 Hz

ν=293.53 Hz

please give thanks, click heart! :)

apparently it is wrong, but my work and online calculator says otherwise... possibly round your answer? I'm not sure then...

Answer:146.75

Explanation:

Given: Distance (x) covered by the ball = 180 m, maximum height (y) reached by the ball = 21.3 m The trajectory followed by the ball can be modelled using the equations of motion. The initial velocity of the ball is 31.63 m/s.

The equations of motion relate the displacement, velocity, time and acceleration of the moving body. The general equation of motion for vertical motion under gravity is: y = u sinθt - 1/2 gt²where y is the vertical displacement, u is the initial velocity, θ is the angle of projection, g is the acceleration due to gravity and t is the time taken to reach the maximum height.

The maximum height is given by: (u y = 0)t = u sinθ/g Solving for t, we have: t = (u sinθ)/g Therefore, the equation of motion becomes: y = (u²sin²θ)/ 2 g Putting the given values in the above equation:21.3 = (u² sin² 45)/ (2 x 9.8) => u = 31.63 m/s Therefore, the initial velocity of the ball is 31.63 m/s.

Learn more about initial velocity visit : brainly.com/question/29110645

#SPJ11

Answer:

F = 144 N

Explanation:

For this exercise we will use Neqwton's second law. Let's fix a reference system with the x-axis in the direction of the sled, let's write the forces for each part

Sack, let's use subscript 1

Y axis  

       N₁-W₁ = 0

       N₁ + W₁ = m₁ g

X axis

       fr₁ = m a₁

the expression for the friction force is

       fr = μ₁ N₁

we substitute

        μ₁ m₁ g = m a₁

Sled, subscript 2

Y axis

       N₂ - W₁ -W₂ = 0

       N₂ = W₁ + W₂

       N₂ = (m₁ + m₂) g

X axis

       F - fr₁ -fr₂ = m a₂

the expression for the deroce force is

      fr = μ N

we substitute

       F - μ₁ m₁g - μ₂ (m₁ + m₂) g = m a₂

as it indicates that the velocity is constant the acceleration of the sled is zero (a₂ = 0)

       F = μ₁  m₁g + μ₂  (m₁ + m₂) g

       F = g (m₁ (μ₁ + μ₂) + μ₂ m₂)

let's calculate

       F = 9.8 (50 (0.07 + 0.1) + 62 0.1)

       F = 144 N