Answer:
a) 75 J
b) 37.5 J
c) 0
Explanation:
Work is the force exerted on an object causing it to move, Work is the product of force and displacement. Work is not done if the force and displacement are at right angles to each other. It is given by:
[tex]Work(energy)=Fxcos(\theta)[/tex]
F is the force, x is the displacement and Θ is the angle between force and displacement.
a) Force (F) = 15N and distance (x) = 5. Since it is in the direction of the force, Θ = 0
[tex]Work(energy)=Fxcos(\theta)= 15*5*cos(0)=75J[/tex]
b) Force (F) = 15N and distance (x) = 5. Θ = 60
[tex]Work(energy)=Fxcos(\theta)= 15*5*cos(60)=37.5J[/tex]
c) Force (F) = 15N and distance (x) = 5. Θ = 90
[tex]Work(energy)=Fxcos(\theta)= 15*5*cos(90)=0[/tex]
A 4.0 kg block is initially at rest on a frictionless, horizontal surface. The block is moved 8.0 m by the application of a constant 10.0 N horizontal force. If the block slides into a fixed horizontal spring and comes to rest when the spring is compressed a distance of x=0.25m. Determine the spring constant of the fixed horizontal spring. Show all formula with substitutions and units.
Answer:
k = 2560 N/m
Explanation:
To find the spring constant, you take into account that all the kinetic energy of the block becomes elastic potential energy in the spring, when the block compressed totally the spring:
[tex]K=U\\\\\frac{1}{2}mv^2=\frac{1}{2}kx^2[/tex]
m: mass of the block = 4.0kg
v: velocity of the block just before it hits the spring
x: compression of the spring = 0.25m
k: spring constant = ?
You solve the previous equation for k:
[tex]k=\frac{mv^2}{x^2}[/tex] (1)
Then, you have to calculate the velocity v of the block. First, you calculate the acceleration of the block by using the second Newton law:
[tex]F=ma[/tex]
F: force over the block = 10.0N
a: acceleration
[tex]a=\frac{F}{m}=\frac{10.0N}{4.0kg}=2.5\frac{m}{s^2}[/tex]
With this value of a you can calculate the final velocity after teh block has traveled a distance of 8.0m:
[tex]v^2=v_o^2+2ad[/tex]
vo: initial velocity = 0m/s
d: distance = 8.0m
[tex]v=\sqrt{2ad}=\sqrt{2(2.5m/s^2)(8.0m)}=6.32\frac{m}{s}[/tex]
Now, you can calculate the spring constant by using the equation (1):
[tex]k=\frac{mv^2}{x^2}=\frac{(4.0kg)(6.32m/s)^2}{(0.25m)^2}=2560\frac{N}{m}[/tex]
hence, the spring constant is 2560 N/m
PLEASE HELP!!!!!
When describing image formation for plane mirrors, what is an important rule
to remember about light rays?
Answer: The image formed by a plane mirror is always virtual (meaning that the light rays do not come from the image), upright and of the same shape and size as the object it is reflecting.
Answer: B. The angle when it leaves is the same as the angle when it hits
Explanation:
Apex
A 1.2 m steel rod moves through a uniform magnetic field of 0.020 T at 30 m/s. What emfis induced between the two ends of the steel rod?
0.36 V
0.50 V
0.60 V
0.72 V
Answer:
0.50v
Explanation:
Now EMF is induced when there is motion of a conductor in an electric field. Michael Faraday in the annals of scientific history discovered this.
This is expressed mathematically as;
E = Magnetic field / t
but t = d/ v; d- distance, v-velocity, time
Hence E = magnetic field/ d/v
= Magnetic field× v/ d
= 0.02×30/ 1.2= 0.5
Which force does not operate at a distance of 1 m?
A. Weak nuclear
O B. Electric
C. Gravitational
D. Magnetic
Answer:
A
Explanation:
You get in your car to drive to school at 7:33 am and drive 10 miles north at a constant speed until 7:45
am, when you realize you left your homework on the kitchen table. You turn around and drive 10 miles
south back to your house and retrieve your homework at 8:00 am. You get back in the car and drive 15
miles north to school at a constant speed arriving at school at 8:29 am sharp, just in time to make it
before the bell rings.
e
Answer:
5.) 16.8 m/s
6.) 16.1 mph
7.) Moving fast.
Explanation:
5.) From the question, the total time will be:
7:33 am to 7:45 am = 12 minutes
As the car turns around,
7 : 45 am to 8 : 00am = 15 minutes
As you get back in the car and drive 15
miles north to school at a constant speed arriving at school at 8:29 am
8:00am to 8:29 am = 29 minutes
Total time = 12 + 15 + 29 = 56 minutes
Convert the minutes to second by multiplying the result by 60
Total time = 56 × 60 = 3360 seconds
Total distance covered will be
10 miles + 10 miles + 15 miles = 35 miles
Convert mile to meter by multiplying the result by 1609.344
35 × 1609.344 = 56327.04
Speed is a scale quantity. It only involves magnitude but no direction.
Average speed = total distance/total time
Average speed = 56327.04/3360
Average speed = 16.764 m/s
6.) Velocity = displacement/time
Velocity is a vector quantity. We will consider both the magnitude and direction
Total displacement = 10 miles - 10 miles + 15 miles = 15 miles.
Total time = 56 minutes
Convert minutes to hours by dividing it by 60
Total time = 56/60 = 0.93 hours
Substitute the time and displacement into the formula
Velocity = 15/0.93 = 16.07 mph
7.) . If you looked at your speedometer on your drive to school and it read 30mph, this value describes you move with a fast speed.
Please explain it’s in the photo
Answer:
Since air resistance actually stops vehicles and goes in a vector opposite to the direction of the vehicle and slows it down. Vehicles would want to make vehicles aerodynamic. Many cars bump into air molecules therefore making air resistance. Aerodynamic cars will lesser the allowance of bumping into said molecules. Thats why cars like to cut down on air resistance
Air resistance is friction.
-- Friction steals kinetic energy.
-- A car gets kinetic energy by burning gasoline, and uses the kinetic energy to get where it needs to go.
-- If anything steals the car's kinetic energy, then the car has to burn more gasoline to get where it needs to go.
-- Gasoline costs money.
-- Anything that steals a car's kinetic energy costs you more money to operate the car.
(Another thing that takes kinetic energy away from the car is the car's brakes. The driver uses the brakes when he WANTS to slow down or stop, so it's not stealing, but it still costs kinetic energy and money.)
An astronaut is moving in space when a big explosion occurs about 50 meters behind him. How will the astronaut come to know about the explosion?
Choose:--
From the sound of the explosion
From the light due to the explosion
From light and sound due to the explosion
From the vibrations due to the explosion
Answer:
The correct answer is B.
The astronaut will know due to the light from the explosion.
Explanation:
Sound and vibrations require a medium such as air to travel through. Space, there is no air. Only a vacuum. So sound and vibrations are unable to travel. Light requires no medium to travel. It can go through a vacuum.
Therefore the Astronaut will see a bright flash of light as it travels from the explosion to outer space. It is also important to note that light can travel very far because nothing else interacts with its wave particles and as such, it cannot be impeded.
Cheers!
A car starts from rest and attains a velocity of 30m/s in 5 sec . calculate the total distance travel by that car and acceleration
Answer:
Acceleration (a) = 6 m/s²
Total distance travel by car(s) = 75 meter
Explanation:
Given:
Initial velocity (u) = 0
Final velocity (v) = 30 m/s
Time (t) = 5 sec
Find:
Total distance travel by car(s) = ?
Acceleration (a) = ?
Computation:
v = u +at
30 = 0 + a(5)
30 = a(5)
Acceleration (a) = 6 m/s²
Total distance travel by car(s) = ut +1/2(a)(t)²
Total distance travel by car(s) = 1/2(a)(t)²
Total distance travel by car(s) = (0.5)(6)(5)²
Total distance travel by car(s) = 75 meter
state two factors that affect the turning effect of force
Answer:The first is the magnitude of the force applied on the body and the second is the perpendicular distance from the line of action of force and the axis of rotation of the body.
Explanation:
In which space, outdoors or in your classroom, would it be easier to hear a musician? Explain
Answer:
It is easier to hear a musician in the classroom than outdoors
Explanation:
It is easier to hear a musician in the classroom due to the improved acoustics provided by the walls of the classroom whereby along with the direct sound of the musician, which is the lead source of the sounds, there is an increased number of indirect sound reaching the ear in the classroom than outdoors and due to precedence effect, all the sound appear to come from the musician
In music played outside, along side the direct sound from the musician, the indirect sound that reach the ear is echoed from maybe by only the ground while the majority of the sound from the music wanders away with the wind and in other directions as well as being absorbed such that speakers will be required to improve the sound of the music outdoors.
Why did the Founding Fathers want to include a bill of rights in the U.S.
Constitution?
A. To ensure that the government couldn't take away the individual
rights of citizens
B. To provide future generations a way to amend, or change, the
Constitution
C. To allow states to write and approve their own state constitutions
D. To give state governments more power than the federal
government
Answer:
Its A
Explanation:
Thats because federalists wanted to take away rights. But the fathers wanted to definitely ensure that each person had equal rights and liberty.
How much power is used by 4 A appliance that is plugged into a 120 V circuit for 4 minutes
Answer:
Power, P = 480 W
Explanation:
It is required to find the power used by 4 A appliance that is plugged into a 120 V circuit for 4 minutes. Power used by an appliance is given by the formula as follows :
[tex]P=VI[/tex]
Plugging all the values we get :
[tex]P=120\times 4\\\\P=480\ W[/tex]
So, the power used by the appliance is 480 W.
a 50.0kg bicyclist on a 10.0kg bicycle speeds up from a 5.00m/s to 10.0m/s
Answer:
The total kinetic energy before accelerating = 750 JThe total kinetic energy after accelerating = 3,000 JTotal work done = 2,250 JExplanation:
Given:
Mass of bicyclist = 50 kg
Mass of bicycle = 10 kg
Initial velocity (u) = 5 m/s
Final velocity (v) = 10 m/s
Find:
(a) What was the total kinetic energy before accelerating = ?
(b) What was the total kinetic energy after accelerating = ?
(c) How much work was done to increase the kinetic energy of the bicyclist = ?
Computation:
Total mass (M) = 50 kg + 10 kg = 60 kg
1. The total kinetic energy before accelerating = 1/2[Mu²]
The total kinetic energy before accelerating = 0.5[(60)(5)²]
The total kinetic energy before accelerating = 750 J
2. The total kinetic energy after accelerating = 1/2[Mv²]
The total kinetic energy after accelerating = 0.5[(60)(10)²]
The total kinetic energy after accelerating = 3,000 J
3. Total work done = Δ K.E
Total work done = 3,000 J - 750 J
Total work done = 2,250 J
Explain two applications of resonance
PLEASEEEE HELP ME!
Answer:
in physics, resonance is a phenomenon in which a vibrating system or external force drives another system to oscillate with greater amplitude at specific frequencies. example a familiar example is a playground swing, which acts as a pendulum.
hope this helped!
state the principle of conservation of energy
Answer:
Principal of Conservation of Energy states that " Energy is neither created nor destroyed. However, It is just converted to other forms of energy"
Solar energy is a form of
energy from the Sun.
OA) heat
OB) nuclear
OC) mechanical
OD) electromagnetic
Answer:
Solar energy is a form of Electromagnetic energy
Explanation:
Solar energy is constantly flowing away from the sun and throughout the solar system. Solar energy warms the Earth, causes wind and weather, and sustains plant and animal life. The energy, heat, and light from the sun flow away in the form of electromagnetic radiation (EMR
Isaac throws an apple straight down from a tree with an initial speed of 5.0 \dfrac{\text m}{\text s}5.0 s m 5, point, 0, start fraction, start text, m, end text, divided by, start text, s, end text, end fraction. It hits the ground with a final speed of 12 \dfrac{\text m}{\text s}12 s m 12, start fraction, start text, m, end text, divided by, start text, s, end text, end fraction. How many seconds did the apple fall?
Answer:
0.71s
Explanation:
From Newton's law of motion ;
V =U +gt
V is the final velocity or speed
U is the initial velocity or speed
g is acceleration of free fall due to gravity given as 9.8m/S2
Note when a body moves horizontally down its said to do so with the aid of the force of gravity
Hence the final velocity is aided by gravity.
From the above formula;
t =V-U/ g
t= 12-5/ 9.8 = 0.71s
Answer: .71
Explanation:
Khan academy
what is brightness. help asap
Answer:
The subjective visual sensation related to the intensity of light emanating from a surface or from a point source.
Earth receives some of the Sun's energy in the form of heat and light.
What type of energy does heat and light from the Sun begin as?
O A) nuclear
OB) chemical
OC) electrical
OD) mechanical
Answer:
a) nuclear
Explanation:
Ed biked home from school in 400 seconds. His home is located 2000 m south of the school. What was his velocity?
[tex]answer = 5 \: \: metre \: per \: second\\ distance = 2000 \: m \\ time = 400 \: seconds \\ velocity = \: \frac{distance \:t ravelled}{time \: taken} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \frac{2000}{400} \\ \: \: \: \: \: \: \: \: \: = 5 \: metre \: per \: second \\ hope \: it \: helps[/tex]
A remote controlled plane accelerates to a velocity of 21.0 m/s while covering a distance of 87.4 m in 6.11 s. What was the plane's initial velocity?
Answer:
7.61 m/s
Explanation:
Given:
Δx = 87.4 m
v = 21.0 m/s
t = 6.11 s
Find: v₀
Δx = ½ (v + v₀) t
87.4 m = ½ (21.0 m/s + v₀) (6.11 s)
v₀ = 7.61 m/s
71.6
Δx = 87.4 m
v = 21.0 m/s
t = 6.11 s
Find: v₀
Δx = ½ (v + v₀) t
87.4 m = ½ (21.0 m/s + v₀) (6.11 s)
v₀ = 7.61 m/s
In simple terms describe diffraction, refraction and reflection. Give examples for each.
Answer:
Refraction is the bending of life an example would be how when you put a straw in a glass and it looks like the straw gets detached from itself. Reflection is when light bonces off of something an example would be a mirror.
Explanation:
The way a mirror works is the light you see bounces off of the glass and gives your optical sensors the vision of what the glass reflected.
Answer:
Diffraction , refraction and reflection all are property of light that shows its wave nature.
Explanation:
What is diffraction?When a light ray passes through a narrow single slit , the superposition of secondary wavelets produced by the same source , is called diffraction.
Example ; Single slit experiment in which the diffraction shows maxima and minima .
What is refraction ?The banding of light due to variation in the speed of light when it travels from one medium to another is called refraction.
Example; Divergence or convergence by lenses.
What is reflection ?The bouncing back of light from a surface is called reflection.
Example : Mirrors.
Hence all the given topics are explained.
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A device has power -2 D . The device is
a.A convex lens of focal length 50 cm
b.A concave lens of focal length 50 cm
c.A convex lens of focal length 2 m
d.A concave lens of focal length 2 m
Answer:
b.
Explanation:
-vesign shows the lens is CONCAVE
f=1/power
Which objects would sink in honey, which has a density of 1.4 g/cm³? Check all that apply.
Answer:
any object that has density more than 1.4
Explanation:
The object that has density more than 1.4 is denser than the honey
which refers to a transfer of thermal energy between two objects?
A. potential energy
B. kinetic energy
C. heat
D. temperature
When salt is added to the water what happens to the surface?
Answer:
it increases the surface tension of the water
A ramp is a simple machine called the
a. wedge
b. pulley
c. inclined plane
d. lever
Answer:
Inclined Plane is the answer
Answer:
Inclined plane
Explanation:
It is called Inclined plane since it is a flat surface at an angle.
People often think that Galileo dropped two objects of dramatically different mass off of the Leaning Tower of Pisa that both hit the ground at the same time. Explain why in reality this was most likely not true.
Answer: because of air resistance. See explanation for further details.
Explanation: Galileo performed an experiment to proof that the time of descent of two different masses is independent of time.
But in reality this is most likely not true because of air resistance and other fluid frictional effects in consideration.
If the experiment is performed in a vacuum, it will always be true that time is independent of masses of two falling objects.
50 COINS AMAZING PLEASE HELP ME!!!
Answer:
ok
Explanation:
Ok
!! i will mark as brainliest so pls answer quick !!
The student becomes negatively charged because of the friction between her socks and the carpet.
Explain why the friction causes the student to become charged
Answer:
A student becomes negatively charged because of the friction between his socks and the carpet. ... The electrons get rubbed and move towards the carpet so the carpets electrons move away and the student becomes negatively charged.