To solve this problem, we must remember about the law of
conservation of momentum. The initial momentum mist be equal to the final
momentum, that is:
m1 v1 + m2 v2 = (m1 + m2) v’
where v’ is the speed of impact
Since we are not given the masses of each car m1 and m2,
so let us assume that they are equal, such that:
m1 = m2 = m
Which makes the equation:
m v1 + m v2 = (2 m) v’
Cancelling m and substituting the v values:
50 + 48 = 2 v’
2 v’ = 98
v ‘ = 49 km/h
<span>The speed of impact is 49 km/h.</span>
First,

where
is density,
is mass, and
is volume. We can compute the volume of the roll:


When the roll is unfurled, the aluminum will be a rectangular box (a very thin one), so its volume will be the product of the given area and its thickness
. Note that we're assuming the given area is not the actual total surface area of the aluminum box, but just the area of the largest face (i.e. the area of one side of the unrolled sheet of aluminum).
So we have

where
is the given area, so


If we're taking significant digits into account, the volume we found would have been
, in turn making the thickness
.
Answer:
4.08 s
Explanation:
Let the passenger took "t" time to catch the train
so in this case the total distance moved by the train + 5 m = total distance moved by the passenger
so we will have
distance moved by train is given as

also the distance moved by passenger

so we will have



t = 4.08 s