Answer:

Explanation:
Let say the empty wagon has mass "M"
now by newton's II Law we will have

now it is given that empty wagon is pulled with acceleration 1.4 m/s/s
now we will have

now a child of mass three times the mass of wagon is sitting on the empty wagon
so here we have


so we have

Answer:
The strong person should carry the ladder at the front end and the weak person should carry it at the back end.
Explanation:
this is because in such a case the strong person has to pull the ladder whereas the weak person at the back end have to push the ladder. In such case it is easier to push because the weak person can use the force of gravity of his own body for pushing the ladde.
However in case of pulling the ladder one has to overcome his own gravity to pull the heavy object
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<h2><em>I Hope it help you </em></h2>
First, convert all the km/hr into m/s
You will get that
initial speed = 20 m/s
Initial speed of Green train = 40 m/s
Initial separation = 950 m
Velocity of approach = 20 - -40 = 60 m/s
relative acceleration = -4 m/s^2
v = u + at
0 = 60 - 4t
t = 15s
s = ut + 1/2 *at * t
s = 60 * 15 - 1/2 *4 * 225
s = 900 - 450
Separation when they stop = 450 m
hope this helps
Answer:
I think that the liquids molecules are slowing down. Hope this helps!
Explanation:
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This makes frequency lower as well as the pitch we hear.