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,

Answers

Answer 1

Answer:

B. An opposing force caused by friction produced a lower acceleration than calculated

Explanation:

Answer 2

Answer:

An opposing force caused by friction produced a lower acceleration than calculated.

Explanation:


Related Questions

Select the correct answer from each drop-down menu.
What causes atoms to form covalent bonds?
The number of
In a covalent bond, two atoms are held together by the attraction between
covalent bonds that an atom can form depends on the number of
in the atom.

Answers

Answer:

YES the first option

Explanation:

two atom are held together

Answer:

In a covalent bond, two atoms are held together by the attraction between each atom and the shared electrons. The number of covalent bonds that an atom can form depends on the number of valence electrons in the atom.


A baseball bat strikes a baseball of mass that is at rest, and as a result the baseball files away from the bat. The kinetic energy gained by the
baseball as it leaves the bat is due to the
(A) loss of mass after the ball is hit.
(B) gain in potential energy as the ball rises to the peak of its trajectory
(C) loss of potential energy of the ball as it falls back to the ground
(D) work done by the bat on the ball

Answers

Answer:

The correct option is D

Explanation:

When an object at rest is acted upon by an external force, the motion gained (of the body) will proceed in the direction of the force. This is caused by the workdone by the bat on the ball. The motion gained mentioned earlier is the kinetic energy.

Kinetic energy can be described as the energy in a moving object.

Answer:

(D) work done by the bat on the ball

Explanation:

The principle of work-energy theorem, states that work done by the sum of all the forces acting on an object, is equal to the gain in the kinetic energy of the object.

When the baseball bat strikes the baseball which causes a displacement in the initial position of the baseball, work is said to be done which is equal to the change in the kinetic energy of the baseball.

Thus, The kinetic energy gained by the baseball as it leaves the bat is due to the work done by the bat on the ball.

A annoying small child is dropped off a 16.0 m cliff (for complaining about homework). The
speed the child will reach right before they hit the ground is
m/s - Don't worry,
the child will not sustain life threatening injuries as they ended up doing all their homework
and therefore was saved by the magical Physics Creature.
(Record your answer to correct significant digits).

Answers

Answer:

i would be that annoying child lol

Explanation:

but i just needed this for points sorry :>

fill in the word that completes the statement. the direction of the magnetic field produced by an electric current will change when the direction of the _____ changes​

Answers

Answer:

current trust me thoo pls

Answer:

Current

Explanation:

Right on edge ✅

If an object has a fast velocity, the dots on a ticker tape diagram will be _____.

very long
far apart
very short
close together

Answers

Answer:

If an object has a fast velocity, the dots on a ticker tape diagram will be far apart.

I’m pretty sure the answer is “very long”

How much net force must Mrs. McD’s 30,000 kg jet plane develop to achieve an acceleration of 1.5 m/s2?

Answers

F = MA
30,000 kg * 1.5 m/s^2 = 45,000 N

Convert 318 meters per second to kilometers per hour

Answers

Answer:

1144.8

Explanation:

1 meter per second is equal to 3.6 kilometers per hour

list two animals that migrate to the clearing

Answers

Sea animals and birds

A weight lifter is trying to lift a 1,500 N weight but can apply a force of only 1,200 N on the weight. One of his friends helps him lift it at a constant velocity. What force was applied to the rope

Answers

Answer:

400N is applied to the rope

Answer:

300N

Explanation:

Assuming his friend didn't throw the box, they would need a total of 1,500N to lift it, if the first person is already applying 1,200N, the only other amount of force needed is 300N to make a total of 1,500N! Simple math problem :)

Hope this helps! <3

know the types of peer pressure describe all of them​

Answers

Answer:

Spoken Peer Pressure

Positive Peer Pressure

Direct Peer Pressure

Negative Peer Pressure

Positive Peer Pressure

Unspoken Peer Pressure

Indirect Peer Pressure

Sorry this is all I know

Hope this Helps!

In a physics lab, students take a long piece of string and cut it into two unequal pieces. One piece is used to suspend a large weight. The second piece is tied to the bottom of the weight as seen in the diagram below. Student 1 predicts that the upper string will always break first since it has to support the weight and the applied force, while Student 2 disagrees and predicts that the shorter piece of string will always break first if you pull slowly but with enough force to exceed the strength of the string.

(a) Which aspect(s) of Student 1’s reasoning, if any, are correct? Explain your answer.


(b) Which aspect(s) of Student 2’s reasoning, if any, are correct? Explain your answer.


(c) Which aspect(s) of both Student 1’s and 2’s reasoning, if any, are incorrect? Explain your answer.

(d) The experiment is performed and both students are surprised to learn that whether
the upper or lower string breaks first depends on whether you pull slowly or with a
sudden pull. Resolve the two lines of reasoning of Student 1 and Student 2 by
explaining the results of the experiment in a clear, concise paragraph.

Answers

Answer:

(a) The aspect of the upper string supporting the weight and the applied force

Student 1 is correct because the upper string is the source of support of the large weight and the force applied to the short string reacts at the support of the long string

(b) The aspect of Student's (2) reasoning that is correct is that the shorter piece of string will always break first, however, the statement is only true for sudden pull due to the increased force experienced by the shorter string from a more rapid change in momentum

(c) The aspect of Student 1's statement that is incorrect is the that the upper string will always break first

The aspect of Student 2's statement that is incorrect is the that the shorter piece of string will always break first

(d) A string will break when subject to a force equivalent to its breaking force. The force experienced by the string increases as the rate of pull (suddenness) increases and the suddenness increases inversely with the length of the string, as such the shorter lower string will break first from a sudden pull before the force of the pull is completely transmitted to the upper string. Whereby the lower string is slowly pulled, the force is evenly transmitted to the upper string which is then taking up the load of the weight and the applied force together and is likely to break first

Explanation:

1. A force acting on an object in the upward direction is 3 N. The force that would
balance this force could be written as
will balance because 3 N + (____
-) =
acts in the
direction.
You that know these forces
The balancing force

Answers

Answer:

See the explanation below

Explanation:

We must perform a sum of forces on the body, that sum of forces is equal to zero. That is, the body is in balance and does not move.

ΣF = 0

3 - 3 = 0

This force is negative and acts by pointing downwards.

Answer: ow consider a book sliding from left to right across a tabletop. Sometime in the prior history of the book, it may have been given a shove and set in motion from a rest position. Or perhaps it acquired its motion by sliding down an incline from an elevated position. Whatever the case, our focus is not upon the history of the book but rather upon the current situation of a book sliding to the right across a tabletop.

Explanation:

know the reasons why people have conflict​

Answers

Answer:

just to have conflict

Explanation:

Answer:

·Some people find enjoyment in conflict. (Negative people and bullies)

·Sometimes the only thing that makes that person feel food is to throw people down.

·Conflict happens when two people disagree.

Explanation:

These are just some but there are many more :)

Hope this Helps

:D

The diagram below shows a force of 5N acting on an object P at an angle of 30° to the horizontal.
By drawing appropriate lines on the diagram using a ruler to determine:
a.)The horizontal component of the 5N force.
b.)The vertical component of the 5N force .​

Answers

Given :

The diagram below shows a force of 5N acting on an object P at an angle of 30° to the horizontal.

To Find :

By drawing appropriate lines on the diagram using a ruler to determine:

a.)The horizontal component of the 5N force.

b.)The vertical component of the 5N force.​

Solution :

Horizontal component is given by :

=F cos θ

=5 cos 30°

= 5×0.866

= 4.33 N

Vertical component is given by :

= F sin θ

= 5 sin 30°

= 5×0.5

= 2.5 N

Therefore, horizontal and vertical component are 4.33 N and 2.5 N.

Hence, this is the required solution.

Plz help plllzzzzzzzz

Answers

im trying to answer but it won’t let me:(

A balloon drifts 140 m toward the west in 45 s; then the wind suddenly changes and the balloon flies 90 m toward the east in the next 25 s. a. What distance did it travel during the first 45 s? b. What distance did it travel during the next 25 s? c. What total distance did it travel? d. What was its average speed during the first 45 s? e. What was its average speed during the next 25 s? f. What was its average speed for the entire trip? g. What was its displacement during the first 45 s? h. What was its displacement during the next 25 s? i. What was its total displacement?

Answers

Answer:

Explanation:

Given

1 ) 140 m west in 45 s .

2 ) 90 m east in 25 s .

a )

distance travelled in first 45 s = 140 m

b ) distance travelled in next 25 s = 90 m

c ) Total distance travelled = 140 m + 90 m

= 230 m

d ) average speed in first 45 s

= distance in 45 s  45

= 140 / 45 = 3.11 m /s

e ) average speed in next 25 s

distance in 25 s / 25

= 90 / 25 = 3.6 m /s

f ) average in entire trip

=  total distance / total time

= (140 + 90) / ( 25 + 45 )

= 3.28 m /s

g )

displacement in first 45 s = 140 m towards west

h )

displacement in next 25 s = 90 m towards east

i )

total displacement = 140 - 90

= 50 m towards west .

Four solutes are added to a solvent. All solutes have the same mass and solubility. The surface areas of four solutes are 2 mm2, 4 mm2, 6 mm2, and 10 mm2. Which solute will dissolve the quickest? 2 mm2 4 mm2 6 mm2 10 mm2

Answers

Answer:

The correct answer is D.) 10 mm2

Explanation:

i just did the test on edge 2020 and got it right

If four solutes that have the same mass and solubility are added to a solvent, the solute that will dissolve the quickest is 10mm².

What is solubility?

Solubility refers to the ability of a substance called solute to form solution with another substance called solvent.

Solubility is dependent on the surface area of the solute as solutes with larger surface area tends to dissolve faster in a solvent and vice versa.

Therefore, this means that if four solutes that have the same mass and solubility are added to a solvent, the solute that will dissolve the quickest is 10mm².

Learn more about solubility at: https://brainly.com/question/15560070

A dart is thrown horizontally at a target's center that is 5.00\,\text m5.00m5, point, 00, start text, m, end text away. The dart hits the target 0.150\,\text m0.150m0, point, 150, start text, m, end text below the target's center.What was the initial horizontal velocity of the dart?

Answers

Answer:

Explanation:

Given

the range = 5.00m (distance moved in horizontal direction)

Height = 0.150m

Required

Initial velocity of the dart

Using the formula for calculating range of a projectile;

R = U√2H/g

5 = U√2(0.15)/9.8

5 = U√0.0306

5 = 0.1749U

U = 5/0.1749

U = 28.59m/s

Hence the initial horizontal velocity of the dart is 28.59m/s

Answer:

28.59

Explanation:

khan academy

if a car has traveled 24km in 2 hours, what is the average speed?

Answers

Answer:

12

Explanation:

----------------............

A rock is thrown upwards at 13.5 m/s. How long does it take to fall back to the ground?

Answers

It will take 27 m/s, you multiply 13.5 because it takes twice as long

Charlie's father built a tree house in their backyard. He constructed a spiral staircase around the tree trunk and installed a ladder. Which will involve more work in climbing up the tree house from the ground?

Answers

Answer:

The spiral staircase will require more work

Explanation:

This is because, work can be calculated as force (which is mass of the individual climbing the stairs in this case) multiplied by distance (or length) of the stairs. The only variable that changes in the work done while climbing any of the two (ladder or spiral staircase) is the distance and it is obvious the length of the spiral staircase will be longer; thus the spiral staircase will involve more work.

What allows us to categorize rocks into the three rock types: Igneous, Sedimentary, and Metamorphic?
Whether or not the rock melts
Involvement of sediment
Process of formation
O Magma or weathering.

Answers

Answer:process of formation

Explanation:

What is the typical response of people to a government that abuses them if they are used to that government?

Answers

Answer:

when a government abuses its power its called tyranny and people might try to overthrow the government

If a force of 12 N is applied to an object
and it accelerates 4 m/s2, what is the
mass of the object?

Answers

Answer:

The answer is 3 kg

Explanation:

The mass of the object can be found by using the formula

[tex]m = \frac{f}{a} \\ [/tex]

f is the force

a is the acceleration

From the question we have

[tex]m = \frac{12}{4} \\ [/tex]

We have the final answer as

3 kg

Hope this helps you

EARTH SPACE SCIENCE.

I NEED HELP ASAP DUE TODAY. PLEASE 20 POINTS

Using the topographic map above, match the description to the letter that it represents.

Highest point on the map-
[ Select ]

Stream flowing to the East-
[ Select ]

Letter near the steepest slope-
[ Select ]

Letter near the flattest area-
[ Select ]

Stream flowing to the North- F

Answers

Answer:

c,e,f,d

Explanation:

please help
im on my sisters acc btw lol

Answers

Answer:

Dumbell flys - Pectoral

One Arm Rows - Latissimus Dorsi (Lat)

Pushdowns - Triceps

Machine Back Press - Shoulders

Explanation:

What is the radius of an automobile tire that turns with a period of 0.091 s and has a linear
speed of 20.0 m/s? What kind of force is the centripetal force?

Answers

Answer:

1) The radius of the tire is approximately 0.28966 meters

2) The centripetal force is the force that keeps a body moving on a circular path

Explanation:

1) The linear speed of the automobile tire = 20.0 m/s

The period with which the tire turns = 0.091 s

The period = The time it takes to make a complete turn

Therefore;

The number of turns in 1 second = 1/0.091 ≈ 10.989 turns

The distance covered with 10.989 turns, assuming no friction = 10.989 × The circumference of the tire

∴ The distance covered with 10.989 turns, assuming no friction = 10.989 × 2 × π × Radius of the tire

From the speed of the car, 20.0 m/s, we have;

The distance covered in 1 second = 20.0 meters

Therefore;

10.989 × 2 × π × Radius of the tire = 20.0 meters

Radius of the tire = (20.0 meters)/(10.289 × 2 × π) ≈ 0.28966 meters

The radius of the tire ≈ 0.28966 meters

2) The centripetal force is the force required to maintain the curved motion of an object, and having a direction towards the center of the rotary motion.

The centripetal force is given by the formula, [tex]F = \dfrac{m \cdot v^2}{r}[/tex]

Where;

F = The centripetal force

m = The mass of the object

v = The linear velocity of the object

r = The radius of the rotational motion.

In a transverse wave wavelength can be measured as the distance between a. Two adjacent crests. b. A crest and the adjacent trough. c. A crest and the resting position. d.None of the above

Answers

Answer:

a)Two adjacent crests

Explanation:

Transverse wave is a moving wave that

in which the point of oscillation is at right angle to the direction of the wave. The particle of the medium of transverse wave usually vibrate at right angle to the wave's direction in up and down movement. Wavelength can be measured in the direction the wave is going can defined as the distance between two successive crest of the particular wave. It can be calculated as Wavelength= velocity/ frequency. Which means where there is higher frequency of the wave, then there will be shorter wavelength.

Hence, transverse wave wavelength can be measured as the distance between Two adjacent crests.

CHECK THE ATTACHMENT FOR THE WAVE FIQURE

The path of a projectile is called a ???

Answers

Answer:

Projectile motion is a form of motion where an object moves in parabolic path; the path that the object follows is called its trajectory.

Explanation:

Disponemos de datos de presión y volumen de tres situaciones de un gas ideal que se han medido manteniendo la temperatura del gas constante representa los valores de un gráfico p-v expresa matemáticamente la ley de Boyle-Mariotte y calcula el valor de la constante

Answers

Answer:

Explanation:

This is an exercise in thermodynamics, the ideal gas equation is

          PV = n R T

In this case the temperature is constant, so

         n R T = cte

throughout the experiment

           

We can write the relationship for the three points 1, 2 and 3

         P₁ V₁ = P₂ V₂ = P₃ V₃ = cte

In the attached graph we can see a graph of this relationship

the data for this graph are

 V(m³)     P ( Pa)

  V₀          P₀

  V₀/2    2 P₀

  V₀/4    4 P₀

for the graph, let it be assumed that V₀ = 1 and P₀ = 1

 

To calculate the value of the constant s, you must know the moles of gas and the temperature at which the experiment is carried out, for example, if we have a mole of gas and room temperature (T = 300K), the constant is

       n R T = 1   8,314  300

       n R T = 2492.2 J

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