Answer:
Well Albert Einstein is more smarter PERIOD
Explanation:
You are driving your car on a very cold late Fall day. You clear a turn and see a couple of pedestrians standing at the cross walk. They are eager to cross the road and to get into the warmth of their apartment as soon as possible. You have two options: continue driving your car as you were without lowering your speed and drive right by the pedestrians OR slow down, stop right at the crosswalk, and yield to the pedestrians. Although by Virginia law the choice is clear, what about Physics laws? Which scenario (passing by or slowing down and stopping at the crosswalk to yield) will minimize the time the pedestrians are out in the cold freezing before they can cross the road?
Make the following assumptions in your argument. Before you noticed the pedestrians, you are moving with a constant velocity v=22 miles/hour. The distance at which you noticed the pedestrians is D=23 meters. Write down a symbolic expression for the amount of time, tpass , the pedestrians will have to wait till they cross the road if you simply drive by without slowing down or speeding up.
Write down a symbolic expression for the amount of time, tstop, the pedestrians will have to wait till they cross the road if you slow down, come to a complete stop at the crosswalk and yield to the pedestrians.
Answer:
t_pass = 2.34 m
t_stop = 4.68 s
Thus, for the car passing at constant speed the pedestrian will have to wait less.
Explanation:
If the car is moving with constant speed, then the time taken by it will be given as:
[tex]t_{pass} = \frac{D}{v}[/tex]
where,
t_pass = time taken = ?
D = Distance covered = 23 m
v = constant speed = (22 mi/h)(1609.34 m/1 mi)(1 h/3600 s) = 9.84 m/s
Therefore,
[tex]t_{pass} = \frac{23\ m}{9.84\ m/s} \\[/tex]
t_pass = 2.34 m
Now, for the time to stop the car, we will use third equation of motion to get the acceleration first:
[tex]2as = v_{f}^{2} - v_{i}^2\\a = \frac{v_{f}^{2} - v_{i}^2}{2D}\\\\a = \frac{(0\ m/s)^{2}-(9.84\ m/s)^2}{(2)(23\ m)}\\\\a = -2.1\ m/s^2[/tex]
Now, for the passing time we use first equation of motion:
[tex]v_{f} = v_{i} + at_{stop}\\t_{stop} = \frac{v_{f}-v_{i}}{a}\\\\t_{stop} = \frac{0\ m/s - 9.84\ m/s}{-2.1\ m/s^2}[/tex]
t_stop = 4.68 s
Constant velocity is the velocity which covers the same distance for each interval of the time.
The time required to pass is 2.34 seconds and the time to stop is 4.68 seconds.
What is constant velocity?Constant velocity is the velocity which covers the same distance for each interval of the time.
It can be given as,
[tex]v=\dfrac{x}{t}[/tex]
As the distance covered by the car is 23 meters and the constant velocity of the car is 22 miles per second.
Convert the unit of velocity in m/s the value obtained will be 9.84 m/s.
Thus amount of time, [tex]t_{pass}[/tex] is,
[tex]9.84=\dfrac{23}{t_{pass} } \\t_{pass} =\dfrac{23}{9.84} \\t_{pass} =2.34[/tex]
As the distance covered by the car is 23 meters and the constant velocity of the car is 22 miles per second.
Convert the unit of velocity in m/s the value obtained will be 9.84 m/s.
Thus amount of time, [tex]t_{pass}[/tex] is,
[tex]9.84=\dfrac{23}{t_{pass} } \\t_{pass} =\dfrac{23}{9.84} \\t_{pass} =2.34[/tex]
According to the third equation of the motion acceleration can be given as,
[tex]v^2-u^2=2ax\\a=\dfrac{v^2-u^2}{2x}\\a=\dfrac{0^2-9.84^2}{2\times 23}\\a=-2.1 \rm \; m/s^2[/tex]
Now, use the first equation of motion, to get the required time,
[tex]v=u+at\\0=9.84+(-2.1)t\\t=4.68\rm \; s[/tex]
Therefore, the time required to pass is 2.34 seconds and the time to stop is 4.68 seconds.
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Suppose that a uniform rope of length L resting on a frictionless horizontal surface, is accelerated along the direction of its length by means of a force F, pulling it at one end. A mass M is accelerated by the rope. Assuming the mass of the rope to be m and the acceleration is a. Stated in terms of the product ma, what is the tension in the rope at the position 0.3 L from the end where the force F is applied if the mass M is 1.5 times the mass of the rope m?
Answer:
2.2 ma
Explanation:
Given :
Length of the rope = L
Mass of the rope = m
Mass of the object pulled by the rope = M
M = 1.5 m
So, L [tex]$\rightarrow$[/tex] m
For unit length [tex]$\rightarrow \frac{m}{L}$[/tex]
∴ 0.3 L = [tex]$0.3 \ L \left(\frac{m}{L}\right)$[/tex]
= 0.3 m
And for remaining 0.7 L = [tex]$0.7 \ L \left(\frac{m}{L}\right)$[/tex]
= 0.7 m
By Newtons law of motion,
F - T = ( 0.3 m) a .........(1)
T = ( M + 0.7 m) a
T = ( 1.5 m + 0.7 m) a
T = ( 2.2 m ) a ..............(2)
So from equation (1) and (2), we have
Tension on the rope
T = 2.2 ma
Which word best completes the sentence?
Select the word from the drop-down menu
He is quite
Choose...
despite never having left his smalL TOWEN
Answer:
it’s cosmopolitan
Explanation:
k12
Please help me with this 29 points
Answer:
)Give the definition of poverty line as defined by the World Bank.
One of the smallest planes ever flown was the Bumble Bee II, which had a mass of 180 kg. If the pilot’s mass was 70 kg, what was the velocity of both plane and pilot if their momentum was 20,800 kg∙m/s to the west?
Answer:
83.2 m/s to the West
Explanation:
From the question given above, the following data were obtained:
Mass of plane = 180 Kg
Mass of pilot = 70 Kg
Momentum = 20800 Kg∙m/s West
Velocity =?
Next, we shall determine the total mass. This can be obtained as follow:
Mass of plane = 180 Kg
Mass of pilot = 70 Kg
Total mass =?
Total mass = Mass of plane + Mass of pilot
Total mass = 180 + 70
Total mass = 250 Kg
Finally, we shall determine the velocity. This can be obtained as follow:
Total mass = 250 Kg
Momentum = 20800 Kg∙m/s West
Velocity =?
Momentum = mass × Velocity
20800 = 250 × Velocity
Divide both side by 250
Velocity = 20800 / 250
Velocity = 83.2 m/s West
Thus, the velocity of both plane and pilot is 83.2 m/s to the West
The (BLANK) island were where Darwin made many important observations.
Answer:
I know theirs South American coast he was there a lot
An instructor wishes to determine the wavelength of the light in a laser beam. To do so, she directs the beam toward a partition with two tiny slits separated by 0.180 mm. An interference pattern appears on a screen that lies 5.30 m from the slit pair. The instructor's measurements show that two adjacent bright interference fringes lie 1.60 cm apart on the screen. What is the laser's wavelength (in nm) ?
Answer:
λ = 5.434 x 10⁻⁷ m = 543.4 nm
Explanation:
To solve this problem we can use the formula provided by Young's Double Slit experiment:
[tex]\Delta x = \frac{\lambda L}{d}\\\\\lambda = \frac{\Delta xd}{L}[/tex]
where,
λ = wavelength of light = ?
Δx = distance between adjacent bright fringes = 1.6 cm = 0.016 m
d = slit separation = 0.18 mm = 0.00018 m
L = Distance between slits and screen = 5.3 m
Therefore,
[tex]\lambda = \frac{(0.016\ m)(0.00018\ m)}{5.3\ m}[/tex]
λ = 5.434 x 10⁻⁷ m = 543.4 nm
A screw-jack used to lift a bus is a
A) first order lever
B) second order lever
C) pulley
D) screw
when is an object considered to be in motion
Answer:
An object is considered to be in motion only when its position changes over time with reference to a point which will be known as orgin
You push a 1.5 kg ball across a desk for 2 seconds, so that 10 J of work have been done. How much power was produced?
Answer
Answer:
i need help with the same question
Explanation:
During a circus act, an elderly performer thrills the crowd by catching a cannon ball shot at him. The cannon ball has a mass of 39.0 kg and its horizontal component of velocity is 6.50 m/s just before the 65.0 kg performer catches it. If the performer is initially motionless on nearly frictionless roller skates, what is his speed immediately after catching the cannon ball
Answer:
[tex]2.4375\ \text{m/s}[/tex]
Explanation:
[tex]m_1[/tex] = Mass of cannon ball = 39 kg
[tex]m_2[/tex] = Mass of performer = 65 kg
[tex]u_1[/tex] = Initial horizontal component of cannon ball's velocity = 6.5 m/s
[tex]u_2[/tex] = Initial horizontal component of performer's velocity = 0
v = Velocity of combined mass
As the momentum of the system is conserved we have
[tex]m_1u_1+m_2u_2=(m_1+m_2)v\\\Rightarrow v=\dfrac{m_1u_1+m_2u_2}{m_1+m_2}\\\Rightarrow v=\dfrac{39\times 6.5+0}{39+65}\\\Rightarrow v=2.4375\ \text{m/s}[/tex]
The speed of the performer immediately after catching the cannon ball is [tex]2.4375\ \text{m/s}[/tex].
Astronauts living on the International Space Station have zero gravitational acceleration.
True
False
What is the weight of a 25 kg object on Earth with an acceleration due to gravity of 9.8m/s/s?
2.45 n
24.5 n
245 n
2450 n
Netwtons 1st law of motion
Answer:
Newton's first law states that, if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force. This postulate is known as the law of inertia.
Explanation:
3. If a spring extends by 3 cm when a 4 N weight is suspended from it, find the extension
when the weight is changed to
(a) 8 N
(b) 10 N
(c) 14 N
What are characteristics of wide-angle lenses?
it takes a cheetah just 3s to reach its top speed of 30m/s what is it's acceleration
Given values are:
Speed,
v = 30 m/sTime,
t = 3 sAs we know,
→ [tex]Acceleration = \frac{Speed}{Time}[/tex]
or,
→ [tex]a = \frac{v}{t}[/tex]
By substituting the values,
[tex]= \frac{30}{3}[/tex]
[tex]= 10 \ m/s^2[/tex]
Thus the above solution is correct.
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19. In a turtle race, a 20 kg turtle moves with a velocity of 0.1 m/s. What is the kinetic energy of the turtle?
A. 20 J
B. 0.2 J
C. 0.1 J
A ball is thrown straight up with an initial velocity of 128 ft/sec, so that its height (in feet) after t sec is given by s(t) = 128t-16t2. (a) What is the average velocity of the ball over the following time intervals? [3,4] ft/sec [3,3.5] ft/sec [3,3.1] ft/sec (b) What is the instantaneous velocity at time t = 3? ft/sec (c) What is the instantaneous velocity at time t = 6? ft/sec Is the ball rising or falling at this time? rising falling (d) When will the ball will hit the ground? t = sec
Answer:
one sec let me think
Explanation:
(a)The average velocity of the ball over the following time intervals will be [3,4] ft/sec.
(b)The instantaneous velocity at time t = 3 will be32 ft/sec.
(c)The instantaneous velocity at time t = 6 will be -64 ft/sec.
(d)The ball will hit the ground at 13.4 sec.
What is velocity?The change of displacement with respect to time is defined as the velocity. velocity is a vector quantity. it is a time-based component.
The given data in the question will be ,
u is the initial velocity by which ball thrown=128 ft/sec.
V₃ is the instantaneous velocity at time t=3 sec.
V₆ is the instantaneous velocity at time t=6 sec.
t is the time when ball hits the ground=?
(a) Given equation for the displacement
s(t) =128t-16t² (on differenting got the velocity )
v(t) = 128-32t
Time when velocity is zero will be
[tex]\rm{ t=\frac{128}{32}[/tex]
[tex]\rm{ t=4 sec[/tex]
If the velocity got in the equation is 128 and 32 ft /sec. it can be only when the average velocity is [3,4] ft/sec .
Hence the average velocity obtained from the problem will be [3,4] ft/sec
(b)
s(t) =128t-16t² (on differenting got the velocity )
v(t) = 128-32t
At time( t=3 sec)
v(3) = 128-32×3
v(3) =32 m/sec.
Hence the instantaneous velocity at time t = 3 will be32 ft/sec.
(c)
s(t) =128t-16t² (on differenting got the velocity )
v(t) = 128-32t
At time( t=6 sec)
v(6) = 128-32×6
v(6) = -64 m/sec.
Hence the instantaneous velocity at time t = 6 will be -64 ft/sec.
(d)
According to Newtons third equation of motion we got
v=u+gt
If the body returens from a certain height at max height its velocity must be zero; ( u=0)
[tex]\rm t=\frac{(v-u)}{g} \\\\\ \rm t=\frac{(128-0)}{9.81}\\\\\rm t=13.04 sec.[/tex]
Hence the ball will hit the ground at 13.4 sec.
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What x rays travel at the speed of
Help please :)
X-ray waves are transmitted by ....... ?
Answer:
im not sure maybe viberation
Explanation:
Answer:
X-ray waves are transmitted by ....... body tissues with very little absorption
Hope it helps
Please mark me as the brainliest
Thank you
weight is measured in units called
The weight is measured in a unit called Newton. The newton is a standard unit of weight measurements.
The International System of Units (SI) uses Newtons (N) as the unit of weight measurement. Weight is frequently expressed in pounds (lb) or ounces (oz) in some nations that employ the Imperial system. However, Newton is the accepted weight measurement unit in scientific and international contexts.
The International System of Units (SI) uses Newton as the primary unit of weight measurement. Sir Isaac Newton, a great physicist who significantly influenced our understanding of classical mechanics, is honored by having his name attached to it. Newton is the force needed to accelerate a mass of one kilogram by one meter per second squared in the SI system.
Hence, the weight is measured in a unit called Newton. The newton is a standard unit of weight measurements.
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How much power does motor provides an elevator in a building when the total mass when loaded is 500 kg to a height of 3m in 25 seconds?
Help please :)
Infrared waves are transmitted by ....... ?
A screw-jack used to lift a bus is a
A) first order lever
B) second order lever
C) pulley
D) screw
Answer:
c
Explanation:
In what way does water change when condensation occurs?
from gas to liquid
from liquid to solid
from liquid to gals
from solid to liquid
An official major league baseball has a mass of 0.14 kg. A pitcher throws a 40 m/s fastball which is hit by the batter straight back up the middle at a speed of 46 m/s.
a) What is the change in momentum of the ball during the collision with the bat?
b) If this collision occurs during a time of 0.012 seconds, what is the average force exerted by the bat on the ball?
Answer:
(a) The change in momentum is 12.04 kg-m/s
(b) The force exerted by the bat is 1003.33 N
Explanation:
Given that,
The mass of a ball, m = 0.14 kg
Initial speed of the ball, u = 40 m/s
Final speed of the ball, v = -46 m/s
(a) The change in momentum of the ball during the collision with the bat is given by :
[tex]\Delta p=m(v-u)\\\\=0.14(-46-40)\\\\=-12.04\ kg-m/s[/tex]
(b) Time for collision, t = 0.012 s
Now the force can be calculated as follows :
[tex]F=\dfrac{\Delta p}{t}\\\\F=\dfrac{12.04}{0.012}\\\\=1003.33\ N[/tex]
Hence, this is the required solution.
Answer:
a. = 12.04 kg*m/s
b. = 1,003.3N
Explanation:
The answer above is correct.
it takes 840s to walk completely around a circular track, moving at a speed of 1.20m/s? what is the radius of the track?
Answer:
160.43 meters
Explanation:
T=(2*pi*r)/v
840=(2*pi*r)/1.2
1008=2*pi*r
504=pi*r
160.43=radius
The distance around the circular track is equal to its circumference. If it takes840 s to complete the path with a velocity of 1.20 m/s then the radius of the path will be 160 m.
What is velocity?Velocity is a physical quantity measuring the distance traveled by unit time. It is a vector quantity thus, characterized by its magnitude and direction. Velocity is usually expressed in m/s.
Velocity is the ratio of distance to the time taken to complete the travel. Thus, greater distance within short time indicates greater velocity.
Given that the time take to complete the circular path = 840 s
velocity = 1.20 m/s
distance = circumference of the circular path = 2πr.
distance = time × velocity
2πr = 840 s × 1.20 m/s
= 1008 m.
Therefore, the radius r of the circular path = 1008 m/ 2 π = 160 m.
Hence, the radius of the circular path 160 m.
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Which statement best describes this situation
Answer:
what situation?
Explanation:
6xy from -12xy
please give me a answer this question
6 floors down from 12 floors underground = 18 floors underground.
6 degrees colder than 12 degrees below zero = 18 degrees below zero
6 brown cows taken away from -12 brown cows = -18 brown cows
6 cars sold from a dealer that 12 cars were stolen from = 18 cars gone
6xy taken away from -12xy = -18xy