Answer:
Velocity (magnitude) is 98.37 m/s
Explanation:
We use the vertical component of the initial velocity, which is:

Using kinematics expression of vertical velocity (in y direction) for an accelerated motion (constant acceleration, which is gravity):

Now we need to find
as a function of
. We use the horizontal velocity, which is always the same as follow:

We know the angle at 3 seconds:

Substitute
in
and then solve for 

With this expression we go back to the kinematic equation and solve it for initial speed

The answer is d) batteries
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Answer:
- It is vital for all known forms of life.
- It provides no calories nor organic nutrients.
- It forms precipitation in the form of rain and aerosols in the form of fog.
- It's chemical symbol is H₂O
Explanation:
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At the highest point: kinetic energy is 0 due to the speed is 0
So the total mechanical energy is 20
Assume no frictions present, then the mechanical energy is conserved
So at the lowest point, kinetic energy = mechanical energy - potential energy
Answer will be 20 - 0.5 = 19.5 J
Newton's second law states that the force applied to an object is equal to the product between the mass m of the object and its acceleration a:

Using

and

, we can find the value of the force applied to the roller-blade to obtain this acceleration: