Valid Expressions are; t = ∛(d²/va), a = d/t², a = √(vd/t³), v = at
while the Invalid expressions are; v = a/t and d = at
Explanation:
Given expressions
1) v = a/t
2) t = ∛(d²/va)
3) d = at
4) a = d/t²
5) a = √(vd/t³)
6) v = at
First we get our units of parameters
V = m/s, t = sec, d = m, a = m/s²
so
1)
v = a/t
we substitute in our units of parameters
v = m/s² / s = m/s² × 1/s = m/s³
v ≠ m/s³
therefore it is false
2)
t = ∛(d²/va)
we substitute
t = ∛(m² / m/s × m/s²)
t = ∛(m² / m²/s³)
t = ∛(s³)
t = s
correct, the expression is true
3)
d = at
we substitute
d = m/s² × s
d = m/s² × s/1 = ms/s² = m/s
d ≠ m/s (because d = m)
so expression is false
4)
a = d/t²
we substitute
a = m / s² = m/s²
correct
the expression is true
5)
a = √(vd/t³)
we substitute
a = √(m/s×m / s³) = √(m²/s / s³) = √(m²/s × 1/s³) = √(m²/s⁴) = m/s²
so a = m/s²
correct
the expression is true
6)
v = at
we substitute in the units
v = m/s² × s = m/s² ×s/1 = ms/s² = m/s
v = m/s
correct
the expression is correct
A boy pulls a wagon with an applied force of 40 N on frictionless surface. If the mass of the wagon is 13kg, what is the acceleration of the wagon?
Answer:
3.1 m/s²
Explanation:
Apply Newton's second law:
∑F = ma
40 N = (13 kg) a
a ≈ 3.1 m/s²
A 10,000 kg freight car moving at 2 m/s collided with a stationary 30,000 kg freight car. The two cars couple together and move off at what speed?
Answer:
Explanation:
Momentum conservation:
10,000 x 2 = (10,000 + 30,000) x v
so
v = 0.5 m/s
The speed after collision will be = 0.5m/s
What is conservation of momentum ?The conservation of momentum states that the amount of momentum remains constant , momentum is neither be created nor be destroyed but only changes through the actin of forces as described by newton's law of motion
since , momentum should be conserved before and after the collision
so , from momentum conservation we can write ,
m1 = mass of moving freight car = 10000kg
v1 = speed of moving freight car = 2m/s
m2 = mass of stationary freight car = 30000 kg
v2 = speed of stationary freight car = 0 (since , at rest )
M = mass of coupled cars after collision
V = velocity coupled cars after collision
momentum before collision = momentum after collision
m1*v1 + m2*v2 = MV
10000 * (2) + 30,000 * 0 = (10000 + 30000) V
20000 = 40000V
V = 0.5 m/s
The speed after collision will be = 0.5m/s
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An ideal fluid is moving at 3.0 m/s in a section of a pipe of radius 0.20 m. If the radius in another section is 0.35 m, what is the flow speed there
The flow speed of the fluid in the second section of the pipe is 0.98 m/s
What is flow speed?Flow speed is the rate at which the distance of a fluid changes with respect to time as it moves in a pipe.
To calculate the flow speed in the second section, we use the formula below.
Formula:
AV = A'V'............ Equation 1Where:
A = Cross-sectional area of the first section of the pipeV = Velocity of fluid in the first section of the pipeA' = cross-sectional area in the second section of the pipeV' = Velocity of fluid in the second section of the pipe.Make V' the subject of the equation
V' = AV/A'......... Equation 2From the question,
Given:
A = πR² = 0.04π m²V = 3 m/sA' = πr² = (0.35²×π) = 0.1225π m²Substitute these values into equation 2
V' = 3(0.04π)/(0.1225π)V' = 0.98 m/sHence, The flow speed of the fluid in the second section of the pipe is 0.98 m/s
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In size, composition, and color, which other planet is Saturn most like?
A) Jupiter
B) Earth
C) Venus
D) Mercury
If the man has a mass of 90kg, where would he experience greater gravitational force? On Earth or Moon? Calculate and explain
Answer: You feel the gravitation on the Earth greater
Explanation:
Because the mass of the Earth is heavier than the Moon, you can replace specifi number of the weight of the Moon and the man compare the weight of the Earth and the man into the formula!
A 100V battery connected to two oppositely charged plates that are 10cm apart.
a. What is the magnitude of the electric field?
b. What is the electric force exerted on a +200uC ?
Answer:
Work to move unit charge from one plate to the other separated by d
W = E q d
Electric potential: V = W / q
E = V / d = 100 Volts / .1 m = 1000 Volts / m
F = E q = 1000 Joule / C m * 2 * 10E-4 C
F = .2 J / m = .2 N
PLEASE HELP QUICKLY
Jason shoots a nerf dart at 13 m/s horizontally, while Jake drops
same time. Which dart hits the ground first?
O Jason's
O Jake's
O There is not enough information to know
They both hit at the same time
Answer:
they both hit at the same time
A container is filled to a depth of 154.7 cm with water. On top of the water floats a 124.5 cm thick layer of oil with specific gravity 0.754. What is the absolute pressure at the bottom of the container
does a radio wave have a high or low frequency
Answer:
Low
Explanation:
Radio waves have photons with the lowest energies.
Calculate the displacement and then velocity for an object 12.77s after it is dropped.
Answer:
799 m
125 m/s
Explanation:
Take down to be positive. Given:
v₀ = 0 m/s
a = 9.8 m/s²
t = 12.77 s
Find: Δy and v
Δy = v₀ t + ½ at²
Δy = (0 m/s) (12.77 s) + ½ (9.8 m/s²) (12.77 s)²
Δy ≈ 799 m
v = at + v₀
v = (9.8 m/s²) (12.77 s) + 0 m/s
v ≈ 125 m/s
Describe how a sound wave travels through a medium to create sound.
A soundwave will go through a medium but once it goes through, the sound that you hear is muffled or not as clear usually just like sound going through a wall. The soundwaves will be something like moved and the sound you hear might not be the same or as clear as the original sound was
Answer:
sound waves
Explanation:
The sound waves can go through different mediums depending on the crest and trough
Question 3 of 10
What happens to the resistance of a wire as its length decreases?
A. The resistance alternates between high and low values.
B. The resistance increases
ОО
C. The resistance is not affected by a change in wire length.
O D. The resistance decreases.
SUBMIT
B
The resistance of a wire is directly proportional to length of wire. Hence the more the length of wire, the more its resistance.
According to The first law thermodynamics Energy can be created and destroyed, True or False? 
Answer:
False
Explanation:
energy in terms I've heard at least energy cannot be created or destroyed
If 2 J of wok is done in raising a 180 g red delicious apple to bring it to your mouth to take a bite of the apple, how far is it lifted?
Answer:
Most likely 2ft
Explanation:
Your arm aint that long
Can someone pls help ! I’m sorry it’s small
Answer:
The velocity time graph which shows a negative constant velocity (horizontal line below the horizontal axis) Labeled as Graph #2
Explanation:
Notice that the position-time graph shows the position decreasing in the form of a line with negative slope. Recall that the velocity graph is associated with the change in position with time, and this change in position is in the form of a line of constant negative slope. The slope of the position-time graph is in fact the velocity of the object, which therefore is negative and constant.
Such behavior is represented by the graph labeled as Graph 2 of a constant (horizontal) line below the horizontal axis.
find the kenitic energy before and after the collision
Answer:
The total system kinetic energy before the collision equals the total system kinetic energy after the collision. If total kinetic energy is not conserved, then the collision is referred to as an inelastic collision.
Explanation:
Initial kinetic energy KE = 1/2 m1v12 + 1/2 m2v22 = joules. The following calculation expects you to enter a final velocity for mass m1 and then it calculates the final velocity of the other mass required to conserve momentum and calculates the kinetic energy either gained or lost to make possible such a collision.
Describe Health and Exercise
Answer:
plenty of exercise
Explanation:
If you are unhealthy or not happy with yourself. try this. Do a 30 minute walk everyday and eat normal amounts of food portions a human should have an in a day. Make sure you drink plenty of water. If that doesn't work maybe taking to someone about it and see what information they have for you. These things do work because i was over weight and lost 73 pound just by doing those few things.
-- can some someone please help ----How far did the object move between 0 and 20 s?
m____________
An object with a mass of 9 kg weighs 33.3 N on Mars. What is the acceleration due to Mar's gravity?
O 1.6 m/s^2
O 9.8 m/s^2
O 3.7 m/s
O 8.9 m/s
Answer:
3.7m/s^2
Explanation:
Weight (W)= mass (m) x acceleration due to gravity (g)
therefore
g = W/mg
g = 33.3/9
9 = 3.7m/s^2
What does the atomic number of an atom tell us?
Answer:
The atomic number uniquely identifies a chemical element. It is identical to the charge number of the nucleus. In an uncharged atom, the atomic number is also equal to the number of electrons. The sum of the atomic number Z and the number of neutrons N gives the mass number A of an atom.
Explanation:
Answer:
I believe that the atomic number of an atom represents the number of protons in one atom of an element. It also tells you the number of electrons in a neutral atom of that element
Explanation:I hope that this is helpful.
Can someone pls help ASAP:(
A child in a boat throws a 6.6kg package out horizontally with a speed of 10.2m/s. Calculate the velocity of the boat immediately after, assuming it was initially at rest. The mass of the child is 29.9kg, and that of the boat is 44.7kg. Ignore water resistance.
Answer:
[tex]-0.902 \frac ms[/tex]
Explanation:
We apply conservation of momentum here. Before the toss, everything was still, so the momentum was 0. After the toss, we have the sum of the momentum of the package (1st term) and the boat+child combo (2nd term). Let's call v the velocity of the boat.
[tex]0= 6.6kg \cdot 10.2\frac ms + (29.9+44.7)kg\cdot v\\v= - \frac{6.6 \cdot 10.2 }{74.6} \frac ms \approx -0.902 \frac ms[/tex]
The term is negative since it expresses the boat+child system is going the opposite way from where the package flew.
PLEASE HELP WILL GIVE BRAINLIEST
A cheetah can run at instantaneous speeds of 64 km/hr or 17.8 m/sec. How much time does it take a cheetah to run 2 m?
0.1 seconds
0.1 m/s
35.6 seconds
0.03 seconds
A bus run at 100 km/hr top speed. It can carry a maximum of 6 persons. If speed of bus decreases in fixed proportion with increase in number of person, find speed when three person are traveling in bus.
Answer:
150 km/h
Explanation:
It is given that,
Speed of a bus is 100 km/h and it can carry a maximum of 6 persons.
If speed of bus decreases in fixed proportion with increase in number of person, then we need to find the speed when 3 person are traveling in bus.
6 person = 100 km/h
1 person = (100/6) km/h
Ans
3 person = [tex]\dfrac{100}{6}\times 3=50\ km/h[/tex]
Net speed = 100 km/h + 50 km/h = 150 km/h
Hence, if the required speed is 150 km/h.
A compact car can climb a hill in 10 s. The top of the hill is 30 m higher than the
bottom, and the car's mass is 1,000 kg What is the power output of the car?
Answer:
29.4 kW
Explanation:
time t = 10 s, height h = 30 m, mass m = 1,000 kg
power output = work done/time
work done = increase in potential energy = mgh = 1,000 * 9.8 * 30 = 294,000 J = 294 kJ
power output = 294/10 = 29.4 kW
What do you think you could do to help prevent or stop cyberbullying? List at least two ideas.
Answer:
1. You can block the person bullying you.
2. Tell an adult about whats going on.
3. Try to stay off any social media apps. (turn off all notifications)
4. Don't respond to any of the comments or post. (Ignore them)
Explanation:
Hope this helps.
What causes the shock you receive from when you touch a doorknob?
Neutrons being pulled from one
surface to another
Protons being pulled from one surface to another
Electrons being pulled from one surface to another
Positrons being pulled from one surface to another
Answer:
Electrons being pulled from one surface to another
Explanation:
The movement of electrons creates electrical charge.
We can talk about the amountofpotential energy per unit chargeas a function of locationâwe use the term voltageto describe this.A voltage difference between two locations results from the presence of an electric field. The more work the field can do in moving thecharge from point A to point B, the higher the voltageof point A is relative to point B.
Required:
a. Describe and draw the electric field between two large, oppositely charged plates.
b. Electric potentialis completely analogous to an object being dropped off of a building. The higher the building, the more potential energy the object has. Make a sketch of the ground and a building anddraw lines that indicate constantpotential energyof an object.
c. On your sketch for part a, draw lines of constant potential (these are called equipotentiallines). It may help to imagine placing a positive charge between the plates. It will accelerate toward the negative plate and run into it. Regardless of where you place the charge on an equipotential line, itâll hit the negative plate with the same speed.
Answer:
potential lines that are perpendicular to the electric field, they must be parallel to the plates
Explanation:
A and C) for this drawing, as the electric field lines go from the positive plate to the negative plate and are horizontal to the potential lines that are perpendicular to the field, they must be parallel to the plates, see attached part a
B) in this case the ground has an energy of zero and the lines are parallel to the ground, see attached part b
Read the following selections from the section "Mickey Guyton's Star-Spangled Banner."
The Grammy Award-nominated country singer delivered a soaring, emotional version of the anthem largely on bet
own. A small choir and piano later joined her.
Guyton did not appear to drop or flub any words. She wore a royal blue gown.
What conclusion is BEST Supported by the selections?
A- Mickey Guyton has performed at some of the previous Super Bowls.
B- Mickey Guyton spent a great deal of time practicing for her performance.
C- Mickey Guyton was nervous about singing the national anthem mostly on her own.
D- Mickey Guyton put her personal touch on an anthem that came off without a hitch.
Answer:
C
Explanation:
what does the area between the line and the x axis represent on a velocity vs time graph
the area bounded by the line and the axes of a velocity-time graph is equal to the displacement of an object during that particular time period
Thank you
The area between the line and the x axis represent on a velocity vs time graph is the displacement.
The area under velocity-time graph is known as displacement.
In velocity-time graph, the y-axis represents the velocity axis while the x-axis represents the time axis.
Velocity is defined as the change in displacement per change in time.
[tex]v = \frac{dx}{dt}[/tex]
where;
[tex]dx[/tex] is the change in displacement[tex]dt[/tex] is the change in timeThe integration of the velocity gives the area under the curve and that will be equal to the displacement.
[tex]\int\limits^a_b {v} \, dt = x[/tex]
Thus, the area between the line and the x axis represent on a velocity vs time graph is the displacement.
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