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Ymorist [56]
3 years ago
14

A car accelerates uniformly from 10 m/s to 20 m/s in 4.2 seconds. what is the magnitute of its acceleration

Physics
2 answers:
oksian1 [2.3K]3 years ago
8 0

Connexus Physics pre-ap semester A final exam, all correct answers. And y’all better be freaking grateful, because it took a long time to type all this out.

<span>1)      </span>In the steps of the scientific method…
A. Interpreting results

<span>2)      </span>The radius of the Earth is…
B. 6.37 x 10^3 km

<span>3)      </span>Which of the following equations best describes…
D. y = 1/2x

<span>4)      </span>In the graph, what is the correct description…
C. Negative position

<span>5)      </span>The motion of a ball on an inclined plane is described…
C. vi

<span>6)      </span>Acceleration due to gravity is also called
C. free-fall acceleration

<span>7)      </span>Which of the following is a physical quantity…
A. vector

<span>8)      </span>In a coordinate system, a vector is…
A. Cos (theta)

<span>9)      </span>Which of the following is an example of projectile motion?
B. a thrown baseball

<span>10)   </span>A newton is equivalent to which…
A. kg * m/s^2

<span>11)   </span>In the free-body diagram shown below, which of the following…
C. 4050 N

<span>12)   </span>A net force of 6.8 N accelerates a 31 kg scooter…
A. 0.22 m/s^2

<span>13)   </span>A change in the gravitational force acting…
C. Weight

<span>14)   </span>A passenger on a bus moving east sees a man standing on a curb…
C. move west at a speed that is equal to the bus’s speed.

<span>15)   </span>In which of the following scenarios is no net work done?
B. A car travels at a constant speed on a flat road.

<span>16)   </span>What is the kinetic energy of a 0.135 kg baseball thrown at 40.0 m/s?
C. 108 J

<span>17)   </span>Which of the following refers to the sum of kinetic energy…
D. mechanical energy

<span>18)   </span>Which of the following are not units of power?
B. J

<span>19)   </span>Which of the following…can be used to…calculate…change in…momentum?
D. (delta)p = F (delta) t

<span>20)   </span>Two skaters stand facing…
B. their momenta are equal but opposite.

<span>21)   </span>In an inelastic collision…
D. the momentum of one object will increase by the amount that the momentum of the other object decreases.

<span>22)   </span>When an object is moving with uniform circular motion…tangential speed
C. is constant

<span>23)   </span>Which units would be the most appropriate to use to…
A. newtons

<span>24)   </span>How would the speed of Earth’s orbit around the sun change…
A. The speed would not change

<span>25)   </span>A girl pushes a box that has a weight of 450 N up an incline…force of 150 N along…
B. 3.0

<span>26)   </span>According to the law of conservation of mechanical energy,
C. Total energy must remain the same

<span>27)   </span>The potential energy of a 60 kg man…balcony 43 meters…
A. 25000 J

<span>28)   </span>If two small beakers of water, one at 70C and one at 80C…
C. The final temperature is between 70C and 80C

<span>29)   </span>Why does sandpaper get hot when it is rubbed against rusty metal?
C. Friction between the sandpaper and metal…

<span>30)   </span>Which of the following describes a substance in which the temperature and pressure…
D. substance undergoing a change of state

<span>31)   </span>An ideal gas system is maintained at a constant volume of 4 L. If pressure is constant…
A. 0 J

<span>32)   </span>Which of the following is a thermodynamic process in which a system…
C. a cyclic process

<span>33)   </span>When a drop of ink mixes with water…
A The system’s entropy increases, and the total entropy of the universe increases.

<span>34)   </span>A mass-spring system can oscillate…
D. elastic potential

<span>35)   </span>If a semi-truck decrease its speed from 10 m/s to 5 m/s...
D. ¼ its old kinetic energy

<span>36)   </span>A boy releases a small 1 kg toy truck from rest down a 5 meter high hill…
B. 50 J

<span>37)   </span>A car accelerates uniformly from 10 m/s to 20 m/s in 4.2 seconds…
A. 2.4 m/s^2

<span>38)   </span>What must the minimum tension of a single vertical wire be to support a 1.5 kg picture?
A. 15 N

<span>39)   </span>Why does it seem harder to start sliding a couch across a carpeted floor than…
C. The opposing force of friction is greater when an object starts from rest…

<span>40)   </span>An elevator weighing 2.00 c 10^5 N is supported by a steel cable…
Fw =  mass * gravitational acceleration
2*10^5 = mass * 9.8
mass of the elevator = 20.4*10^3 kg

Fnet = Tension – Fw
mass * acceleration = Tension – 2*10^5
20.4*10^3 * 3 = Tension – 2*10^5
61200 = Tension – 2*10^5
Tension = (61200) + (2*10^5)
Tension = 2.61 * 10^5 newton

<span>41)   </span>A bullet with a mass of 6.00 g is fired through a 1.25 kg block of wood on a frictionless surface.
0.006(896) + 0 = 0.006(435) + 1.25(V)
5.376 + 0 = 2.61 + 1.25(V)
5.376 = 2.61 + 1.25(V)
2.766 = 1.25(V)
V = 2.21 m/s

<span>42)   </span>Find the final equilibrium temperature when 10.0 g of milk at 10.0C is added to 1.60 x 10^2 g of coffee with a temperature of 90.0C.
Heat lost = heat gained
X = equilibrium temperature
Heat lost = 160(90-x)
Heat gained = 10(x-10)
14400 – 160x = 10x -100
170x = 14500
X = 14500/170
X = 85.25 degrees





Dafna1 [17]3 years ago
6 0
A=Vf-Vi/t
a=20m/s-10m/s/4.2s
a=2.4m/s^2
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A piece of gum is stuck to the outer edge of a horizontal turntable, which is revolving at a constant speed. The shadow of the g
cestrela7 [59]

Answer:

angular frequency of the table must be same as the frequency of the projection of the gum on the wall

Explanation:

Since we know that the projection on the wall is the vertical component of the position of the gum on the rotating table

So here we will say

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angular frequency of the table must be same as the frequency of the projection of the gum on the wall

7 0
4 years ago
Plz help fast!!
barxatty [35]
We are asked to compare two series circuits having equal number of light bulbs.
1st circuit is powered by 6 batteries each having a voltage of 1.5V
2nd circuit is powered by a single battery having a voltage of 9V.
The six batteries in the 1st circuit can be connected together in series or in parallel.
When the batteries are connected in series (positive terminal of one battery connected to negative terminal of another battery) their voltage gets added which means
Voltage of pack = number of batteries*voltage of each battery
Voltage of pack = 6*1.5
Voltage of pack = 9 volts
But the current remains same in the series connection since there is only path for the current to flow.
On the other hand, when the batteries are connected in parallel, the voltage remains same but the current increases.
Circuit 1:
In this circuit, we have 6 batteries each of 1.5 volts connected in series to provide a voltage of 9 volts.
We have connected 2 bulbs in this series circuit.
The voltage will be equally divided between two bulbs if both bulbs are identical in construction.
So there will be 4.5 volts across each bulb and both bulbs will have same brightness.
Circuit 2:
In this circuit, we have 1 battery which provide a voltage of 9 volts.
We have connected 2 bulbs in this series circuit just like in circuit 1.
The voltage will be equally divided between two bulbs if both bulbs are identical in construction.
So there will be 4.5 volts across each bulb and both bulbs will have same brightness.
Conclusion:
Both series circuits provide a total voltage of 9 volts to the two bulbs connected in series and the voltage will be equally divided among two bulbs and they will have same brightness. Therefore, both circuits will have same characteristics.
5 0
4 years ago
In a certain clock, a pendulum of length L1 has a period T1 = 0.95s. The length of the pendulum
gulaghasi [49]

Answer:

Ratio of length will be \frac{L_2}{L_1}=1.108

Explanation:

We have given time period of the pendulum when length is L_1 is T_1=0.95sec

And when length is L_2 time period T_2=1sec

We know that time period is given by

T=2\pi \sqrt{\frac{L}{g}}

So 0.95=2\pi \sqrt{\frac{L_1}{g}}----eqn 1

And 1=2\pi \sqrt{\frac{L_2}{g}}-------eqn 2

Dividing eqn 2 by eqn 1

\frac{1}{0.95}=\sqrt{\frac{L_2}{L_1}}

Squaring both side

\frac{L_2}{L_1}=1.108

8 0
4 years ago
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