The important thing in this type of questions is to keep track of what you are doing at every point.
From t=0 to t=1s, there is uniform motion at v=24 m/s.
Therefore, it will move 24m in that second of time.
Afterwards, an acceleration comes in, so from t=1s to 11s there will be uniformly accelerated motion with acceleration -6m/s^2.
To account for this, you need to use Suvat's equation:
x(t)=x0+v0*t+1/2*a*t^2.
You should know what to plug in for each of the symbols in this equation:
x0 [initial position at t=1s] = 24m
v0 [initial velocity at t=1s] = 24 m/s
a [acceleration, switched on at t=1s] = -6 m/s^2
t [time from the start of the acceleration until the end, i.e. from t=1s to t=11s] = 10s
Plugging in those numbers in the equation will give you the position at t=11s.
Explanation:
a couple is a system of forces with a resultant moment but no resultant force. A better term is force couple or pure moment. Its effect is to create rotation without translation, or more generally without any acceleration of the centre of mass.
Answer:
the warm air would be up and cool would be down
Explanation:
warm air is less dense and cool air is more dense
I was going to beg off until tomorrow, but this one is nothing like those others.
Why, at only 40km/hr, we can ignore any relativistic correction, and just go with Newton.
To put a finer point on it, let's give the car a direction. Say it's driving North.
a). From the point of view of the car, its driver, and passengers if any,
the pole moves past them, heading south, at 40 km/hour .
b). From the point of view of the pole, and any bugs or birds that may be
sitting on it at the moment, the car and its contents whiz past them, heading
north, at 40 km/hour.
c). A train, steaming North at 80 km/hour on a track that exactly parallels
the road, overtakes and passes the car at just about the same time as
the drama in (a) and (b) above is unfolding.
The rail motorman, fireman, and conductor all agree on what they have
seen. From their point of view, they see the car moving south at 40 km/hr,
and the pole moving south at 80 km/hr.
Now follow me here . . .
The car and the pole are both seen to be moving south. BUT ... Since the
pole is moving south faster than the car is, it easily overtakes the car, and
passes it . . . going south.
That's what everybody on the train sees.
==============================================
Finally ... since you posed this question as having something to do with your
fixation on Relativity, there's one more question that needs to be considered
before we can put this whole thing away:
You glibly stated in the question that the car is driving along at 40 km/hour ...
AS IF we didn't need to know with respect to what, or in whose reference frame.
Now I ask you ... was that sloppy or what ? ! ?
Of course, I came along later and did the same thing with the train, but I am
not here to make fun of myself ! Only of others.
The point is . . . the whole purpose of this question, obviously, is to get the student accustomed to the concept that speed has no meaning in and of itself, only relative to something else. And if the given speed of the car ...40 km/hour ... was measured relative to anything else but the ground on which it drove, as we assumed it was, then all of the answers in (a) and (b) could have been different.
And now I believe that I have adequately milked this one for 50 points worth.
Answer:
8) 1500 feet
9) 20 miles
10) 4 Days
11) 2250 miles
12) 1 hour and 5 minutes
13) 27.27miles per hour
Explanation
8) There are 60 seconds in one minute so 60x25=1500 feet
9) 30 minutes is half of an hour so 40 miles ÷ 2 = 20 miles
10) 12x4=48
11) 500 miles x 4.5 hours is 2250 miles
12) Train leaves at 3pm after 60 miles it will be 4 pm and after 5 more miles 4:05 pm so 1 hour and 5 minutes
13)
Elmo = 40 minutes and 5 miles
Bert and Ernie = 45 minutes and 15 miles
Cookie Monster = 20 minutes and 10 miles
Home = 5 minutes abd 20 miles
Average Speed including stops is 27.27 miles per hour