Given the time, the final velocity and the acceleration, we can calculate the initial velocity using the kinematic equation A:

A skateboarder flies horizontally off a cement planter. After a time of 3 seconds (Δt), he lands with a final velocity (v) of −4.5 m/s. Assuming the acceleration is -9.8 m/s² (a), we can calculate the initial velocity of the skateboarder (v₀) using the kinematic equation A.

Given the time, the final velocity and the acceleration, we can calculate the initial velocity using the kinematic equation A:

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Answer : The final energy of the system if the initial energy was 2000 J is, 3500 J
Solution :
(1) The equation used is,

where,
= final internal energy
= initial internal energy
q = heat energy
w = work done
(2) The known variables are, q, w and 
initial internal energy =
= 2000 J
heat energy = q = 1000 J
work done = w = 500 J
(3) Now plug the numbers into the equation, we get

(4) By solving the terms, we get




(5) Therefore, the final energy of the system if the initial energy was 2000 J is, 3500 J
Answer:
The \: parts \: of \: the \: model \\ airplane \: are \: in \: the \\ same \: proportions \: as \: the \\ actual \: airplane.
Answer:
The distance between them, x = 5809.47 m
Explanation:
Given,
The average weight of a human, w = 600 N
The charge carried by the humans, q = 1.5 C
If 600 N of force acts between two opposite charges, the distance between the charges can be derived from the Coulomb's laws of force,
<em>
</em>
Where,
= 9 x 10⁹ N m² C⁻²
Therefore
x² = 9 x 10⁹ X 1.5² / 600
= 33750000
x = 5809.46 m
Hence, the distance between the humans should be, x = 5809.47 m