calculusxy
  • calculusxy
If the speedometer of a car reads a constant 40km/hr, can you say the car has a constant velocity? Why or why not?
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
katieb
  • katieb
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
calculusxy
  • calculusxy
@Michele_Laino This is like basic physics.
alekos
  • alekos
velocity is defined as speed and direction
Michele_Laino
  • Michele_Laino
I think that we can only say that the magnitude of our velocity is 40 Km/h

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

Michele_Laino
  • Michele_Laino
namely, the motion of our car can be a uniform circular motion
calculusxy
  • calculusxy
So is it a yes?
Michele_Laino
  • Michele_Laino
I think no, since as @alekos as well said the velocity is a vector quantity, which is defined by a speed or magnitude and a direction
calculusxy
  • calculusxy
So since it doesn't have a specific direction it cannot be considered as a "constant velocity," even though it has a constant speed?
Michele_Laino
  • Michele_Laino
yes! That's right!
calculusxy
  • calculusxy
I have more questions, since I like to make sure many things. :)
Michele_Laino
  • Michele_Laino
ok!
calculusxy
  • calculusxy
What two controls in a car can use a change in speed?
calculusxy
  • calculusxy
I wrote the gas and brake pedals. But I am not sure if I should include the steering wheel, since it might change the velocity as well.
Michele_Laino
  • Michele_Laino
I think that you have to include the steering wheel, since by means of the steering wheel we can bend the trajectory of our car, so we can change the velocity of our car
calculusxy
  • calculusxy
So do i write the two pedals (gas and brake) and the steering wheel?
Michele_Laino
  • Michele_Laino
yes! I think so!
sweetburger
  • sweetburger
I agree that the steering wheel would cause a change in direction and therefore could have affect on the velocity
calculusxy
  • calculusxy
Thanks for the continuous help. Next question: What quantity describes how quickly you change how fast you're traveling?
sweetburger
  • sweetburger
Acceleration? right?
calculusxy
  • calculusxy
Yes that's what I thought. But I am not quite sure.
sweetburger
  • sweetburger
change in velocity over time*
Michele_Laino
  • Michele_Laino
right! The steering wheel can produce a centripetal acceleration which is acting on our car @sweetburger
calculusxy
  • calculusxy
@Michele_Laino For this question:What quantity describes how quickly you change how fast you're traveling? Would the answer be "acceleration"?
alekos
  • alekos
Previously you asked "What two controls in a car can change the speed?" (not velocity) that would only be brake and gas pedal.
Michele_Laino
  • Michele_Laino
yes! I think so, since the acceleration, as a number, is the change in speed
sweetburger
  • sweetburger
@alekos I think you are correct considering it is only asking for change in speed.
Michele_Laino
  • Michele_Laino
you are right! @alekos
calculusxy
  • calculusxy
What is the acceleraiton of a car that travels in a straight line at a constant speed of 100km/hr?
calculusxy
  • calculusxy
the acceleration would be 100km/hr since it is travels in a straight line
sweetburger
  • sweetburger
if it is at a constant speed of 100km/hr there is no change in velocity so 0/t = 0
Michele_Laino
  • Michele_Laino
if the speed is constant, then the acceleration as a simple number, and not as a vector quantity, is zero
calculusxy
  • calculusxy
Oh okay
sweetburger
  • sweetburger
the velocity must change over a specific period of time to find a acceleration value
Michele_Laino
  • Michele_Laino
the acceleration as a vector quantity, since the motion is along a straight line, is the null vector
calculusxy
  • calculusxy
What is the acceleration of a car moving along a straight line path that increases its speed from zero to 100km/hr in 10 seconds?
calculusxy
  • calculusxy
Yes that's why i deleted it
Michele_Laino
  • Michele_Laino
we have: 100 Km/h= 27.78 m/sec so acceleration is: 27.78/10=2.778 m/sec^2
calculusxy
  • calculusxy
yeah i was overlooking the "per hour" thank you for correcting that
calculusxy
  • calculusxy
BY how much does the speed of a vehicle moving in a straight line change each second when it is accelerating at 2km/hr (two kilometers per hour per second; that is every second, the velocity is increasing two kilometers per hour.)
Michele_Laino
  • Michele_Laino
after a time t (seconds), the requested change is 2*t Km/h
calculusxy
  • calculusxy
I don't quite understand
Michele_Laino
  • Michele_Laino
by definition, acceleration a is given by the subsequent formula: \[a = \frac{{\Delta v}}{{\Delta t}}\] so we have: \[\Delta v = a\Delta t\]
Michele_Laino
  • Michele_Laino
now, a= 2(Km/h)/sec and if \Delta t= 1 seconds, then we can write: \[\Delta v = a\Delta t = 2 \times 1 = 2\frac{{Km}}{h}\]
anonymous
  • anonymous
ansur at my fb :https://www.facebook.com/ParthKohli
calculusxy
  • calculusxy
What does \[a \Delta t\] mean
calculusxy
  • calculusxy
@Michele_Laino
calculusxy
  • calculusxy
Moving on to the next question: Why does the unit of time never twice in the unit of acceleration?
calculusxy
  • calculusxy
Would it be that the acceleration is found by dividing the velocity by time: \[(distance / time) / time => distance / time^2\]
Michele_Laino
  • Michele_Laino
\[a\Delta t\] is the change in speed
calculusxy
  • calculusxy
So how would i calculate the speed?
calculusxy
  • calculusxy
QUestion: Calculate the speed (in m/s) of a skateboarder who accelerates from rest for 3 seconds down a ramp at an acceleration of 5/m^2.
Michele_Laino
  • Michele_Laino
here we have to apply this formula: \[v = a\Delta t = 5 \times 3 = ...m/\sec \]
calculusxy
  • calculusxy
so for this question would we do: \[V_f = V_i + (acceleration \times time)\]
Michele_Laino
  • Michele_Laino
yes! nevertheless the initial speed is zero, since the skateboarder is starting from the rest
calculusxy
  • calculusxy
V_i = 0 (initial velocity) acceleration = 5 m / s^2 time = 3 seconds \[V_f = 0 + (5 \times 3)\]
Michele_Laino
  • Michele_Laino
that's right!
calculusxy
  • calculusxy
15 m/s ?
Michele_Laino
  • Michele_Laino
yes!
calculusxy
  • calculusxy
THANK YOU SO MUCH!!! Last question: Which has more acceleration when moving in straight line: car increasing its speed rom 50-60km/hr or a bicycle that goes from 0 to km/hr in the same time? Why?
Michele_Laino
  • Michele_Laino
bycicle goes from 0 to ?
calculusxy
  • calculusxy
10km/hr Sorry
Michele_Laino
  • Michele_Laino
if we consider a time interval \Delta t measured in hours, then the acceleration of the car is: \[{a_{CAR}} = \frac{{\left( {60 - 50} \right)}}{{\Delta t}} = \frac{{10}}{{\Delta t}}\;\frac{{Km}}{{{h^2}}}\] whereas the acceleration of the bycicle is: \[{a_{BYCICLE}} = \frac{{\left( {10 - 0} \right)}}{{\Delta t}} = \frac{{10}}{{\Delta t}}\;\frac{{Km}}{h}\]
Michele_Laino
  • Michele_Laino
oops.. \[{a_{BYCICLE}} = \frac{{\left( {10 - 0} \right)}}{{\Delta t}} = \frac{{10}}{{\Delta t}}\;\frac{{Km}}{{{h^2}}}\]
calculusxy
  • calculusxy
So these are both the same right?
Michele_Laino
  • Michele_Laino
sorry for my english: bicycle*
Michele_Laino
  • Michele_Laino
yes! They are the same
calculusxy
  • calculusxy
Thanks!!!!!! I honestly love your help, you have been with me for the past hour!! OMG no one, believe me does that much, except for you!
Michele_Laino
  • Michele_Laino
:)
calculusxy
  • calculusxy
Sorry, but can you explain me the answer for the question: "BY how much does the speed of a vehicle moving in a straight line change each second when it is accelerating at 2km/hr (two kilometers per hour per second; that is every second, the velocity is increasing two kilometers per hour.) "
calculusxy
  • calculusxy
I still didn't get it :(
Michele_Laino
  • Michele_Laino
the speed change as function of time interval \Delta t, is given by the subsequent formula: \[\Delta v = a\Delta t\] where a is the acceleration
Michele_Laino
  • Michele_Laino
in our case, we have: \[a = 2\frac{{Km/h}}{{\sec }}\]
Michele_Laino
  • Michele_Laino
so, if we consider a time interval \Delta t = 1 second, then after that time interval the speed change is: \[\Delta v = a\Delta t = 2 \times 1 = 2\frac{{Km}}{h}\] namely the requested speed change is: 2 Km/h
calculusxy
  • calculusxy
So the answer itself is 2km/hr ?
Michele_Laino
  • Michele_Laino
yes!
calculusxy
  • calculusxy
Thank you! And for the question with the speed from 0 ti 100km/hr in 10 seconds how did you get 27.78 m/sec
Michele_Laino
  • Michele_Laino
since we have to divide by 3.6, namely 100/3.6 = 27.78 (approximated value)
calculusxy
  • calculusxy
why 3.6?
Michele_Laino
  • Michele_Laino
more explanation, we have: \[1\frac{{Km}}{h} = \frac{{1000}}{{3600}}\frac{m}{{\sec }} = \frac{1}{{3.6}}\frac{m}{{\sec }}\]
Michele_Laino
  • Michele_Laino
therefore: \[1\frac{m}{{\sec }} = 3.6\frac{{Km}}{h}\]
calculusxy
  • calculusxy
Oh okay!
calculusxy
  • calculusxy
Thank you soo.... much! May I know what times you are available in OS so that if i need help in physics/math, I can come and ask for your help?
Michele_Laino
  • Michele_Laino
I'am available from 16:00 (Italy time zone)
calculusxy
  • calculusxy
Well I am in NY so what would be the time in EST?
Michele_Laino
  • Michele_Laino
I think 16-6= 9:00 am
Michele_Laino
  • Michele_Laino
sorry: 16-6= 10:00 am
calculusxy
  • calculusxy
oh okay so it's like 8pm in italy now?
Michele_Laino
  • Michele_Laino
yes! at the moment it is 19:57 from me
calculusxy
  • calculusxy
you use the military time a lot?
calculusxy
  • calculusxy
or the 24 hour standard clock?
Michele_Laino
  • Michele_Laino
I use the standard 24 hour clock
calculusxy
  • calculusxy
okay b/c i use am and pm. anyway, thank you so much for your help. i REALLY appreciate it :)
Michele_Laino
  • Michele_Laino
:)

Looking for something else?

Not the answer you are looking for? Search for more explanations.