Answer:
Velocity=5m/s
Explanation:
V=?
S=50m
t=10s
V=S/t
V=50/10
V=5m/s
5.3 two 30 kg children in a 20 kg cart are stationary at the top of a hill. They start rolling down the 80 m tall hill and they are travelling at 30 km h-1 when they reach the bottom. how muvh work was done on the cart by friction during it's travel down the hill
Answer:
60008.4 J
Explanation:
The mass of each kid = 30 kg
mass of the cart = 20 kg
The speed of the cart down the hill = 30 km/hr = 30 x 1000/3600 = 8.33 m/s
The height of the hill = 80 m
The potential energy of the boys at the top of the hill = mgh
where
m is the total mass of the kids and the cart = (30 x 2) + 20 = 80 kg
g is the acceleration due to gravity = 9.81 m/s^2
h is their height above the ground = 80 m (on the top of the hill)
substituting, we have
potential energy PE = 80 x 9.81 x 80 = 62784 J
At an instance at the bottom of the hill
their kinetic energy = [tex]\frac{1}{2} mv^2[/tex]
where
v is their velocity = 8.33 m/s
m is their total mass = 80 kg
substituting, we have
kinetic energy KE = [tex]\frac{1}{2}*80*8.33^2[/tex] = 2775.6 J
Total work done on the cart is equal to the energy lost by the cart when it reached the bottom of the hill
work done by friction = PE - KE = 62784 - 2775.6 = 60008.4 J
Lee skated 36 miles in 3h. What was the speed in which lee stated.
Answer: 12 mph
Explanation: 36 miles divided by 3 hours would be 12 mph
The height of a model rocket h(t) is a function of the time since it was launched t
Answer:
0 [tex]\leq[/tex] t [tex]\leq[/tex] 40
Explanation:
Apex :)
how fast does the light travel in a glass refractive index of 1.5?
Answer:
the light travels at a velocity of [tex]2\,\,10^8 \frac{m}{s}[/tex] in the glass
Explanation:
Recall that the refractive index of a material (n) is defined as the quotient between the speed of light in vacuum (c), and the speed of light in the medium (v). Therefore we can solve for the speed of light in the medium if we know the index of refraction it has:
[tex]n=\frac{c}{v} \\v=\frac{c}{n} \\v=\frac{3\,\,10^8}{1.5} \frac{m}{s} \\v=2\,\,10^8 \frac{m}{s}[/tex]
How can accuracy be limited?
Answer:
accuracy refers to the deviation of a measurement from a standard or true value of the quantity being measured
Who is the father of nuclear physics?
Answer: the father of the nuclear physics is Ernest Rutherford
Explanation:
a dictatorship can also be a democracy
Which phrase is the best definition of matter
Answer:
Matter
Explanation:
Any type of material is a matter. It can be anything that occupies space and have mass. It is a composition of atoms which in term is made up of electrons, protons and neutrons. All particles in our universe is matter because everything has some mass and it occupies space.
Answer:
Anything that has mass and occupies space
Explanation:
Just took the test
The period of a pendulum T depends on a constant g and the length of the pendulum ????in a relation given by
Answer:
The relation is [tex]T = 2\p \sqrt{\frac{l}{g} }[/tex]
Explanation:
Generally the mathematically relation showing the relationship between the period(T), the constant (g) and the length(l) is
[tex]T = 2\p \sqrt{\frac{l}{g} }[/tex]
Ed records the temperature of two pots of water. Pot X
has a temperature of 56 degrees Fahrenheit, and pot Y
has a temperature of 49 degrees Fahrenheit.
Answer is “ the water in pot x has more kinetic energy than the water in pot y”
Answer:
B on edgen
Explanation:
The water in pot X has more kinetic energy than the water in pot Y.
Answer:
the water in pot x has more kenetic energy.
Explanation:
not sure if its the answer. just found it on quizlet.
A motorbike is traveling to the left with a speed of 27.0\,\dfrac{\text m}{\text s}27.0 s m 27, point, 0, start fraction, start text, m, end text, divided by, start text, s, end text, end fraction when the rider slams on the brakes. The bike skids 41.5\,\text m41.5m41, point, 5, start text, m, end text with constant acceleration before it comes to a stop. What was the acceleration of the motorbike as it came to a stop?
Answer:
[tex]\frac{729\frac{m^{2} }{s^{2} } }{83m}[/tex]≈8.8[tex]\frac{m}{s^{2} }[/tex]
Explanation:
Two jars are placed on a counter with a McDonald’s French fry inside. One has a lid, the other does not. They are left alone to see which one decays faster. After two days, the fry in the closed jar looks fresher.
The independent variable is?
The dependent variable is?
What should my conclusion be?
Two students want to determine if the acceleration of an object in free fall depends on the mass of the object. They conduct the following experiment to investigate this question: They drop a balled up sheet of paper (0.005 kg), a notebook (0.4 kg), and their physics book (5 kg) from a height of one meter. If air resistance is ignored, which of the following best predicts which object will experience the greatest acceleration?
Answer:
All the objects experience the same acceleration
Explanation:
According to Newton's law of universal gravitation, we have the gravitational force F given by the relation;
[tex]F=G \times \dfrac{M_1 \times m_{2}}{R^{2}}[/tex]
Where;
G = The universal gravitational constant
M₁ = The mass of the Earth
m₂ = The mass of the object in the Earths gravitational field
R = The radius of the Earth
Therefore, we have;
[tex]F= m_2 \times a = G \times \dfrac{M_1 \times m_{2}}{R^{2}}[/tex]
Which gives;
[tex]a = G \times \dfrac{M_1 }{R^{2}} \ which \ is \ a \ constant = 9.80665 \ m/s^2, \ known \ as \ g, \ which \ is \ \\the \ (acceleration \ due \ to \ gravity)\\[/tex]Therefore, based on the above calculation, all three object will have the same acceleration due to gravity, g, when air resistance is ignored.
Push-ups and lifting weights are good examples of what type of physical activity?
Bone Strengthening Activities
O Muscle Strengthening Activities
Aerobic Activities
Answer:
I think it would be muscle
Explanation:
bones strengthened by calcium
aerobics is more of a gymnastical exercise
leaving a muscle strengthen
Answer:
Technically all 3
Explanation:
Include activities that make their hearts beat faster, build muscles (like climbing or doing push-ups), and strengthen bones (like running or jumping).
Traditional pushups are beneficial for building upper body strength. They work the triceps, pectoral muscles, and shoulders. When done with proper form, they can also strengthen the lower back and core by engaging (pulling in) the abdominal muscles. Pushups are a fast and effective exercise for building strength.Jun 22, 2018
Aerobic exercise (also known as cardiovascular exercise) builds your endurance. Anaerobic exercise typically means activities such as weightlifting and push-ups and sit-ups, which builds muscle and physical strength through short bursts of strenuous activity.
Machines
A pulley system having 5 pulleys is used to
raise a 450 N load. Find the Mechanical
advantage and hence the effort if the
efficiency is 75%.
Explanation:
Hey there!!
Here, Given is,
Efficiency = 75%
VR = no. of pulleys = 5
Now,
[tex]effeciency = (\frac{ma}{vr} ) \times 100\%[/tex]
[tex]75\% = \frac{ma}{5} \times 100\% [/tex]
100% ma = 75%×5
[tex]ma = \frac{75\% \times5}{100\%} [/tex]
[tex]ma = \frac{375\%}{100\%} [/tex]
Therefore, MA is 3.75.
Hope it helps...
Answer:
MA=3.75
Explanation:Given that, E=75%, VR=no. of pulley=5
NOW,
E=(MA/VR)*100%
75%=(MA/5)*100%
MA=(75%*5)*100%
MA=375%/100%
∵MA=3.75
There is a species of bamboo that can grow 36 inches per day. If a plant grew at this rate and was measured at 40 inches initially, how long (in days) would it take for the plant to grow to a height of 200 inches tall?
Answer:
It will take the plant [tex]4\frac{4}{9}[/tex] days or 4.44 days to grow to a height of 200 inches tall.
Explanation:
From the question, the rate at which the species of the bamboo tree grows is 36 inches per day.
To determine how long it would take a plant 40 inches tall initially to grow at this rate (that is, 36 inches per day) to a height of 200 inches.
This means we will calculate the number of days it will take the plant to grow additional 160 inches ( 200 inches - 40 inches) at this rate.
Now,
If the plant grows 36 inches in 1 day
then it will grow 160 inches in x days
x = (160 inches × 1 day) / 36 inches
x = 160 / 36
x = [tex]4\frac{4}{9}[/tex] days or 4.44 days
Hence, it will take the plant [tex]4\frac{4}{9}[/tex] days or 4.44 days to grow to a height of 200 inches tall.
A doctor ran 100 meters in 20 seconds a duck slowly waddled 20 feet in 2 minutes some dude flew 100 miles in 2 hours Dave rolled down a hill he rolled 300 meters 30 seconds
Answer:
1. 50 m/s 2. 10 ft/min 3. 50 miles/hour 4. 10 m/s
Explanation:
We are required to calculate the speed in each instant
Since speed = distance/time,
1. For the doctor, speed = distance/time = 100 m/20 s = 50 m/s
2. For the duck, speed = distance/time = 20 feet/ 2 min = 10 ft/min
3. For the dude who flew, speed = distance/time = 100 miles/ 2 hours = 50 miles/hour = 50 mi/h
4. For Dave who rolled down the hill, speed = distance/time = 300 metres/ 30 s = 10 metres/ second = 10 m/s
An airplane flies 700 miles with a tail wind in 2.0 hrs. If it takes 2.5 hrs to cover the same distance against the headwind, then what is the speed of the plane in still air? A).290mph B).315mph C).240mph D).330mph E).250mph
Answer:
B).315mph
Explanation:
Let the speed of the plane = p
Let the speed of the wind = w
Set up the system equation as;
Relative V: Time: Distance:
in wind direction: p + w 2 700
against wind: p - w 2.5 700
2(p + w) = 700
2.5(p - w) = 700
2p + 2w = 700
2.5p - 2.5w = 700
2.5 x: 5p + 5w = 1750
2 x: 5p - 5w = 1400
10p = 3150
p = 315 mph
Therefore, he speed of the plane in still air is 315 mph
Small blocks A and B are held at rest on a smooth plane inclined at 30° to the horizontal. Each is held in equilibrium by a force of magnitude 18 N. The force on A acts upwards parallel to a line of greatest slope of the plane, and the force on B acts horizontally in the vertical plane containing a line of greatest slope (see diagram). Find the weight of A and the weight of B.
First of all, See the attachment for better understanding[tex].[/tex]
_________________________________
❂ Weight of block A :
➝ mg sin30° = 18
➝ W (1/2) = 18
➝ W = 18×2
➝ W = 36N
❂ Weight of block B :
➝ N sin30° = 18
➝ (Mg cos30°) sin30° = 18
➝ W' (√3/2)(1/2) = 18
➝ W' (√3/4) = 18
➝ W' = 72/√3
➝ W' = 41.61N
what is the mass of 1 litter of liquid in grams, if the density of liquids is 13.6g/ cm^3
Explanation:
1 L = 1000 cm³
m = ρV
m = (13.6 g/cm³) (1000 cm³)
m = 13,600 g
A toy car is moving across a table with a velocity of 7.0 m/s and drives off the end. The table is 1.8 m tall. How long will the car be in the air before it crashes on the floor? a 0.6 seconds b 0.8 seconds c 0.4 seconds d 0.2 seconds
Answer:
Option D - 0.2 s
Explanation:
We are given;
Initial velocity; u = 7 m/s
Height of table; h = 1.8m
Now,since we want to find the time the car spent in the air, we will simply use one of Newton's equation of motion.
Thus;
h = ut + ½gt²
Plugging in the relevant values, we have;
1.8 = 7t + ½(9.8)t²
4.9t² + 7t - 1.8 = 0
Using quadratic formula to find the roots of the equation gives us;
t = -1.65 or 0.22
We can't have negative t value, thus we will pick the positive one.
So, t = 0.22 s
This is approximately 0.2 s
A liquid thermometer can be used to test for fevers. When body temperature increases,
the liquid inside the thermometer expands and rises to show a higher temperature reading. Which of the following explanations below best describes the
changes in thermal energy of the particles during this specific example of heat transfer?
A. The thermometer tip is heated by radiation from the person's body. The particles of the thermometer tip then transfer heat by convection through the
liquid inside of it. The particles inside the liquid then convect heat causing the warmer particles to slow down, expand, and rise.
OB. The thermometer tip is heated by conduction from the person's body. The particles of the thermometer tip then transfer heat by convection through the
liquid inside of it. The particles inside the liquid then convect heat causing the warmer particles to slow down, expand, and rise.
OC. The thermometer tip is heated by convection with the person's body. The particles of the thermometer tip then transfer heat by conduction with the
liquid inside of it. The particles inside the liquid then conduct heat causing the warmer particles to speed up, expand, and rise.
O D. The thermometer tip is heated by conduction with the person's body. The particles of the thermometer tip then transfer heat by conduction with the liquid
inside of it. The particles inside the liquid then convect heat causing the warmer particles to speed up, expand, and rise.
hey m
Answer:A
Explanation:
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A liquid thermometer can be used to test for fevers. When body temperature increases, the liquid inside the thermometer expands and rises to show a higher temperature reading, the explanation that describes the change in the thermal energy,
The thermometer tip is heated by conduction with the person's body. The particles of the thermometer tip then transfer heat by conduction with the liquid inside of it. The particles inside the liquid then convect heat causing the warmer particles to speed up, expand, and rise.
What is thermal energy?It can be defined as the form of the energy in which heat is transferred from one body to another body due to their molecular movements, thermal energy is also known as heat energy.
Conduction with the subject's body heats the thermometer's tip. The liquid inside the thermometer is subsequently heated by conduction between the particles of the thermometer tip. The warmer particles then accelerate, expand, and ascend as a result of the heat convecting through the liquid's particles.
Thus, the correct answer is option D.
Learn more about thermal energy from here
brainly.com/question/3022807
#SPJ2
One of the following statements is incorrect. (a) The car traveled around the circular track at a constant velocity. (b) The car traveled around the circular track at a constant speed. Which statement is incorrect and why?
Answer:
A
Explanation:
It is deemed to be incorrect because velocity deals with displacement. Or in more simple terms, distance in a specified direction.
While moving round the track, the direction keeps changing, so to say and the velocity vector changes constantly.
Speed on the other hand, is a scalar quantity that doesn't bother about nor depends on the direction being taken by the car.
that's all, I hope you understand it all
A baseball is thrown horizontally at 46 m/s. The ball slows down at a rate of 5 m/s2. How long
is the ball in the air before coming to rest?
Answer:
9.2 sExplanation:
Using one of the equation of motion v = u + at where;
v is the final velocity = 0m/s (the ball comes to rest after throw)
u is the initial velocity = 46m/s
a is the acceleration = -5m/s² (the body decelerates)
t is the time taken by the ball in air
substituting the given parameters into the formula to get t, we will have;
0 = 46 +(-5)t
0 = 46 - 5t
subtract 46 from both sides
0-46 = 46-5t-46
-46 = -5t
Divide both sides by -5
-46/-5 = -5t/-5
t = 46/5
t = 9.2seconds
Hence it will take the ball 9.2seconds in the air before coming to rest.
Answer: 9.2sec
Explanation. 9.2sec
Oil dropping down the inner side of a tube confirms amine. This is what analysis ?
Answer:Qualitative
Explanation:
What are the measurements that are used to
describe movement?
Answer: The SI unit
Explanation: The SI units are used to describe the distance an object moves
Solving with the Speed equation: v= d/t
(add to notes if desired)
3. Juan has ridden his bike a total distance of 20 km. If his average speed was 15km/h,
how much time did he ride for?
a)
What is given in the problem? (Circle)
b) What are we trying to find? (Square)
What will be the units to our solution?
d) Plug into the speed equation and solve.
Answer:
Explanation:
time= distance/speed
20km/ 15km/h
= 1 1/3 hours (4/3 in mixed fraction)
There is a hot iron nail and a liter of boiling water. Which one has heat energy? Why?
Guys plz answer it fast
Answer:
Boiling Water.
Explanation:
Because there is still kinetic energy in the water. Thus it has heat energy.
Can someone help me with this?
Answer:
1- origin
2- y coordinate
3- y axis
4- x axis
5- x coordinate
Explanation:
Calculate the workdone by a bricklayer who lifted cement block of mass 10kg from the floor to the height of 3cm g=9.8m
Answer:
The work done is 2.94 Nm.
Explanation:
First, you have to find the force of a brick layer using the formula, Force = mass×gravity :
[tex]f = m \times g[/tex]
[tex]let \: m = 10,g = 9.8[/tex]
[tex]f = 10 \times 9.8[/tex]
[tex]f = 98N[/tex]
Given that the force of a brick layer is 98N. Next, you have to apply work done formula, Work done = force×distance :
[tex]w.d = f \times d[/tex]
[tex]let \: f = 98,d = 0.03m[/tex]
[tex]w.d = 98 \times 0.03[/tex]
[tex]w.d = 2.94Nm[/tex]