Answer:
Option"B" is correct.
Explanation:
when a body move with constant velocity then acceleration is zero.
If the acceleration of an object is 0, it means the velocity of an object is constant and not changing with respect to time,
So, the correct option will be :
=》B)Velocity is constant
What is the magnitude and direction of the net force on a ball that has a force of 27N North and 18N North applied to it?
Answer:
Magnitude: = 32.45 Direction: = 33.69Explanation:
The magnitude of the net force acting on an object is equal to the mass of the object multiplied by the acceleration of the object, as shown in this formula. We find its magnitude using the Pythagorean Theorem or the distance formula, and we find its direction using the inverse tangent function. Given a position vector →v=⟨a,b⟩, the magnitude is found by |v|=√a2+b2. The direction is equal to the angle formed with the x-axis, or with the y-axis, depending on the application.
A ball is thrown straight up from ground level. It passes a 2-m-high window. The bottom of the window is 7.5 m off the ground. The time that elapses from when the ball passes the bottom of the window on the way up, to when it passes the top of the window on the way back down is 1.3 s.
What was the ball’s initial speed, in meters per second?
Answer:
[tex]u=14.48m/s[/tex]
Explanation:
From the question we are told that:
Height of window [tex]h=2m[/tex]
Height of window off the ground [tex]h_g=7.5m[/tex]
Time to fall and drop [tex]t=1.3s[/tex]
Generally the Newton's equation motion is mathematically given by
[tex]s=ut+\frac{1}{2}at^2[/tex]
Where
[tex]h=ut+\frac{1}{2}at^2[/tex]
[tex]2=u1.3-\frac{1}{2}*9.8*1.3^2[/tex]
[tex]2=u1.3-8.281[/tex]
[tex]u=7.91m/s^2[/tex]
Generally the Newton's equation motion is mathematically given by
[tex]2as=v^2-u^2[/tex]
Where
[tex]-2gh_g=v^2-u^2[/tex]
[tex]-2*9.8*7.5=(7.91)^2-u^2[/tex]
[tex]-147=62.5681-u^2[/tex]
[tex]u=\sqrt{209.5681}[/tex]
[tex]u=14.48m/s[/tex]
Therefore the ball’s initial speed
[tex]u=14.48m/s[/tex]
Average running speed is 8km/h. Convert this to m/s :
a)8m/s
b)2.2m/s
c)28.8m/s
d)8km/h
Answer:
Im not sure if you mean miles per hour or meters per hour but if it is miles it is 4.97 miles per hour and if it is meters then it is 8000 meters per hour
Explanation:
Sorry if I'm wrong
3. An object has 90,000 J Kinetic energy and is moving at 12m/s. What is the objects mass?
1. A group of students were trying to find the greatest
rebounded height of a rubber ball dropped on a basketball
court. They dropped from 3 different heights. The chart
below has their data.
26 cm
Drop Height Chart
Trials Drop height Rebound height
Trial 12 meters 103 cm
Trial 2% meter
Trial 31 meter 58 cm
Which explanation is the best reason for why trial 1 has the
greatest rebound height?
A. The speed of the ball is determined by the distance it
travels.
B. The force applied to the ball is a balanced force.
C) The greater the force applied to the ball the greater the
change in motion.
D. The closer the ball is to the ground the more gravity it
has.
Answer:
D th
Explanation:
D B. The force applied to the ball is a balanced force.
ILL GIVE BRAINLIST PLS In which circuit does charge reverse direction many times per second?
A. A DC circuit
B. A combined circuit
C. A parallel circuit D. An AC circuit
Answer: D. An AC circuit
Explanation:
I took it on a test and it was correct ; )
a. Why don't we hear the sound of oscillation of second
pendulum?
Answer:
because the frequency is too low for humans to hear.
Explanation:
Answer:
we cannot hear the sound produced due to vibrations of a seconds' pendulum.
Explanation:
This is because the frequency of sound produced as a result of vibrations of seconds' pendulum is 0.5Hz0.5Hz which is infrasonic sound.
why are the nuclei of the heavier elements radioactive and not the lighter elements of nuclei?
Answer:
becouse most of nuclear elements are heave
Explanation:
1. If a system is isolated, the total energy within that system is constant. Consider the case of a hot cup of coffee: when it cools down, the energy goes into the surrounding air, causing the air to warm. If the coffee and the air are placed in an isolated chamber, the total energy of the system (coffee + air) is constant because the energy lost by the coffee is exactly equal to the energy gained by the air.
The only way for the total energy of a system to change is when it is not isolated, meaning that external forces or sources of energy interact with the system. If we want to define a system where the total energy is conserved, which one of the choices below would be the best system to consider?
A. The person
B. The person and the Earth
C. The Earth
2. Based on your answer to Question 1, why doesn’t the total energy of the Earth-person system change when the person goes up to a new height, gaining potential energy?
Answer:
1. B. The person and the Earth
2. This is because the energy gained by the person equals the energy lost by the earth,
Explanation:
1.
B. The person and the Earth
This is because the person and the earth both represent a system. A system consists of more than one item. A system consists of two or more items interacting with each other.
2. This is because, the energy of an isolated system is conserved according to the second law of thermodynamics which states that in an isolated system, energy can neither be created nor destroyed. So, there is an exchange of energy between the person and the Earth. So, the energy gained by the person at the new height equals the energy lost by the earth. And thus, the total energy of the system remains constant.
what does loudness of a sound depend on?
Answer:
Amplitude
Explanation:
The loudness of a sound depends on the amplitude of vibration producing the sound
Urgent!!!!! A student heated 235 g of water in a beaker until the water reached 100°C. The student removed the beaker from the heat and placed the beaker on a counter in a 23°C room. The student recorded the temperature of the water every 4 minutes for 20 minutes. The data are shown in the table. Estimate the average temperature of the air in the room at 20 min. explain your answer.
The average temperature of the air in the room at 20 min is 23°C.
What is temperature?Temperature is the degree of hotness or coldness of the object.
A student heated 235 g of water in a beaker until the water reached 100°C. The student removed the beaker from the heat and placed the beaker on a counter in a 23°C room. The student recorded the temperature of the water every 4 minutes for 20 minutes.
The surrounding is vast, its temperature does not get affected by small amount of water. So, the temperature of air remains constant.
Thus, the average temperature of the air in the room at 20 min is 23°C.
Learn more about temperature.
https://brainly.com/question/11464844
#SPJ2
The universe cooled after the Big Bang.At some point hydrogen atoms combined to form helium.What is this process called?
Answer:
Nuclear fusion
Explanation:
whem completing an emergency Roaside stop,it is necessary to put on your parking brake
A. True
B. False
Answer:
trueeeeeeee..........mmmm...........
What kind of story would a Romantic audience find MOST appealing?
A. science fiction or futuristic worlds
B. a comedy or something light-hearted
C. one based on Christian morals and piety
D. something where a person disappears in nature
the minimum speed on the interstate highway is
1. 40 mph
2. 60 mph
3. 55 mph
4. 50 mph
I'm in Nebraska btw
Which of the following statements is true concerning the induced current in a coil of wire for a magnet approaching or moving away from the coil?
a. The induced magnetic field repels an approaching magnet.
b. The induced magnetic field attracts a departing magnet.
c. The induced magnetic field always opposes the motion of the magnet.
d. All of the above statements are correct.
Answer:
c
Explanation:
it is c because I hade got it right
A toy car rolls down a ramp. Which force causes the car to move
Answer:
Gravity
Explanation:
Gravity pulls things down to earth and it is a force
physics grade9 teacher guide
Answer:
huh
Explanation:
A skater spins with an angular speed of 5.9 rad/s with her arms outstretched. She lowers her arms, decreasing her moment of inertia by a factor of 1.7. Ignoring friction on the skates, determine the ratio of her final kinetic energy to her initial kinetic energy.
Answer:
the ratio of her final kinetic energy to her initial kinetic energy is 1.7.
Explanation:
Given;
initial angular speed, ω₁ = 5.9 rad/s
let her initial moment of inertia = I₁
her final moment of inertia [tex]I_2 = \frac{I_1}{1.7}[/tex]
Apply the principle of conservation of angular momentum to determine the final angular speed of the girl;
[tex]\omega_1I_1 = \omega_f I_2\\\\\omega_f = \frac{\omega _1 I_1}{I_2} \\\\\omega_f = \frac{5.9 \times I_1}{I_1/1.7} \\\\\omega = 5.9 \times 1.7 \\\\\omega_f = 10.03 \ rad/s[/tex]
The initial rotational kinetic energy is given as;
[tex]K.E_I = \frac{1}{2}I_1 \omega_I ^2[/tex]
The final rotational kinetic energy is given as;
[tex]K.E_f = \frac{1}{2}I_2 \omega_f ^2[/tex]
The ratio of her final kinetic energy to her initial kinetic energy is given as;
[tex]\frac{K.E_f}{K.E_I}= \frac{\frac{1}{2}I_2 \omega_f^2 }{\frac{1}{2} I_1\omega _1^2} \\\\\frac{K.E_f}{K.E_I}= \frac{I_2 \omega_f^2}{ I_1\omega _1^2} \\\\\frac{K.E_f}{K.E_I}= \frac{I_1/1.7 \times \omega_f^2}{ I_1 \times \omega _1^2} \\\\\frac{K.E_f}{K.E_I}= \frac{ \omega_f^2}{ 1.7 \omega _1^2} \\\\\frac{K.E_f}{K.E_I}= \frac{ (10.03)^2}{ 1.7(5.9)^2} = \frac{17}{10} = 1.7[/tex]
Therefore, the ratio of her final kinetic energy to her initial kinetic energy is 1.7.
A rabbit dashes across a field in a zig-zag pattern trying to outrun a fox. If the rabbit’s average is speed is 9.8 m/s it reaches the hole in 8.5 s what is the total distance it ran?
Answer:
83.3 m
Explanation:
From the question,
Applying on of the formula of velocity
V = d/t.................. Equation 1
Where V = average velocity, d = distance, t = time.
make d the subject of the equation
d = V×t................. Equation 2
Given: V = 9.8 m/s, t = 8.5 s
Substitute these values into equation 2
d = 9.8×8.5
d = 83.3 m
Hence the total distance covered by the rabbit is 83.3 m
10 POINTS!! SPACE QUESTION!!
Answer: A (first option)
Explanation: In general, the surface temperatures decreases with increasing distance from the sun. Any warm object in space loses heat via infrared radiation; also visible radiation if it is hot enough. The hotter is the object, the faster it loses heat. Consequently any object warmed by the Sun stays at equilibrium temperature - it warms up until the radiative heat loss equals to the heat received, and cannot get any warmer beyond that.
A sprinter accelerates at 8mps, he weights 850 grams. What
force is he exerting?
How much heat is needed to warm 365 mL of water in a baby bottle from 240C to 38C
Answer:98.6 degrees Fahrenheit
Explanation:
Imagine you are on a space mission and you are 6 AU's from the Sun and you use a light sensor to measure the brightness of the Sun. The amount of sunlight received per square centimeter would be different by what factor compared to the same measurement on Earth at AU
Answer:
36 times less.
Explanation:
The distance from you to the sun is 6AU's, and from the sun to the earth is 1 AU.
Therefore,
At Earth sunlight received per unit cm² is:
[tex]I_{earth} = \dfrac{I_o}{4 \pi \times (1)^2}[/tex]
[tex]I_{earth} = \dfrac{I_o}{4 \pi}[/tex]
[tex]I_{me} =\dfrac{I}{4 \pi (6)^2}[/tex]
[tex]I_{me} = \dfrac{I_o}{36(4 \pi)}[/tex]
Thus, [tex]I_{earth} = 36 \times I_{me}[/tex]
Thus, the right answer is 36 times less.
Classify each change (which can be manipulated within the green box) according to its effect on the wavelength.
a. Decrease frequency
b. Decrease damping
c. Decrease amplitude
d. Increase frequency
e. Increase amplitude
f. Increase damping
g. Shortens wavelength
Answer:
Explanation:
The classification will be made into 3 categories, which are
Ones that shortens wavelengths
Ones that lengthens wavelengths
Ones that has no effect on wavelengths
Shortens wavelengths -> Increase frequency
Lengthens wavelengths -> Decrease frequency
No effect -> Increase amplitude, decrease amplitude, increase damping, decrease damping.
Which of the following is an example of kinetic energy being converted to potential energy?
Answer:
not completed questions
Police radar guns measure the speed of moving vehicles by transmitting electromagnetic waves at a vehicle and detecting a Doppler shift in the reflected wave. Suppose police radar transmits at a frequency of 24.0 GHz and receives a wave reflected from a car moving toward the radar at 65.0 mph. Find the frequency shift Df 5 fO 2 fS between the observed (received) and source (transmitted) frequencies.
Answer:
[tex]4649.20\ \text{Hz}[/tex]
Explanation:
u = Speed of car = 65 mph
[tex]f_s[/tex] = Frequency of source = 24 GHz
c = Speed of light = [tex]3\times 10^8\ \text{m/s}[/tex]
Beat frequency or frequency shift between the observed (received) and source (transmitted) frequencies is given by
[tex]f_o-f_s=\dfrac{2uf_s}{c}\\\Rightarrow \Delta f=\dfrac{2\times 65\times \dfrac{1609.34}{3600}\times 24\times 10^9}{3\times 10^8}\\\Rightarrow \Delta f=4649.20\ \text{Hz}[/tex]
The difference between te required frequencies is [tex]4649.20\ \text{Hz}[/tex].
What does the Curl-up test assess?
O A.
Body composition
ОВ.
Muscular strength and endurance
O C. Flexibility
D.
Cardiovascular fitness
HURRRY
(it’s pe not physics)
Answer:
assesses C.) muscular endurance
Explanation:
A boat travels west at 20km/h. The journey lasts 3hours. How far has the boat travelled?
Answer:
A boat travels for three hours with a... A boat travels for three hours with a current of 3 mph and then returns the same distance against the current in four hours. What is the boat's speed in still water?
Explanation:
500 J of work is used to decrease the angular velocity of a disk from 65 rad/s to 52 rad/s.What is the rotational inertia of the disk?
Answer:
The correct answer is "0.66 kg.m²".
Explanation:
The given values are:
K.E = 500 J
w₁ = 65 rad/s
w₂ = 52 rad/s
As we know,
⇒ [tex]K.E=\frac{1}{2}I[w_1^2-w_2^2][/tex]
then,
⇒ [tex]I=\frac{2(K.E)}{w_1^2-w_2^2}[/tex]
On putting the given values, we get
⇒ [tex]=\frac{2\times 500}{(65)^2-(52)^2}[/tex]
⇒ [tex]=\frac{1000}{4225-2704}[/tex]
⇒ [tex]=\frac{1000}{1521}[/tex]
⇒ [tex]=0.66 \ kg.m^2[/tex]