I am pretty sure the answer would be too stretch
The formula is Ke = 1/2 m v^2
The two of them together have a Ke of mv^2. So you either increase m or v. That's what makes the problem difficult. He can do D or B. We have to choose.
A is no solution. The Ke goes down because Paul loses Ivan's mass.
C is out of the question 3 meters/sec is a big reduction from 5 m/s. So now what do we do about B and D?
The question is what does the third person add. The tandoms I've peddled only allow for 1 or 2 people to add to the motion. So the third person only adds mass. He does not have a v that he is contributing to. To say that he is going 5m/s is true, but he's not contributing anything to that motion.
I pick B, but it is one of those questions that the correctness of it is in the head of the proposer. Be prepared to get it wrong. Argue the point politely if you agree with me, but back off as soon as you have presented your case.
B <<<<====== answer.
Answer:
28.6260196842 m
Explanation:
Let h be the height of the building
t = Time taken by the watermelon to fall to the ground
Time taken to hear the sound is 2.5 seconds
Time taken by the sound to travel the height of the cliff = 2.5-t
Speed of sound in air = 340 m/s
For the watermelon falling

For the sound
Distance = Speed × Time

Here, distance traveled by the stone and sound is equal


The time taken to fall down is 2.4158 seconds

Height of the buidling is 28.6260196842 m
Answer:
0.775
Explanation:
The weight of an object on a planet is equal to the gravitational force exerted by the planet on the object:

where
G is the gravitational constant
M is the mass of the planet
m is the mass of the object
R is the radius of the planet
For planet A, the weight of the object is

For planet B,

We also know that the weight of the object on the two planets is the same, so

So we can write

We also know that the mass of planet A is only sixty percent that of planet B, so

Substituting,

Now we can elimanate G, MB and m from the equation, and we get

So the ratio between the radii of the two planets is

We know that:
F = ma,
so
F/a = constant
F₁/a₁ = F₂/a₂
F₂ = F₁ x 5.6 / 1
F₂ = 5.6F₁
If F₁ = 45 N,
F₂ = 5.6 x 45
= 252 N