Answer:
6.0 m/s
Explanation:
According to the law of conservation of energy, the total mechanical energy (potential, PE, + kinetic, KE) of the athlete must be conserved.
Therefore, we can write:

or

where:
m is the mass of the athlete
u is the initial speed of the athlete (at the bottom)
0 is the initial potential energy of the athlete (at the bottom)
v = 0.80 m/s is the final speed of the athlete (at the top)
is the acceleration due to gravity
h = 1.80 m is the final height of the athlete (at the top)
Solving the equation for u, we find the initial speed at which the athlete must jump:

The answer is B. Unbalanced force
Answer:
Explanation:I don't say you have to mark my ans as brainliest but if you think it has really helped you plz don't forget to thank me ...
A. Plasma
That is your answer!
Answer:
C
Explanation:
velocity = displacement (m) / change of time (s)
velocity = (400 + 300) / (100 + 400)
velocity = 1.4 m/s