Answer:
The speed of the football when it lift your hand is 8.86 m/s.
Explanation:
Given that,
Final speed of the football, v = 0.5 m/s
Height above the ground, s = 4 m
We need to find the speed of the football when it left your hand. The ball will move under the action of gravity. Using third equation of motion as:

So, the speed of the football when it lift your hand is 8.86 m/s. Hence, this is the required solution.
Answer:
Newton's first law of motion states that an object at rest will remain at rest and an object in motion will remain in motion unless it is acted on by an unbalanced force. Using unbalanced forces to control the motion of a skateboard demonstrates Newton's first law of motion.
Hope it helps
Answer: The weight of a girl with a mass of 40kg is 392.266 Newtons.
Explanation:
Take the moment car A starts to accelerate to be the origin. Then car A has position at time <em>t</em>
<em>x</em> = (20.0 m/s) <em>t</em> + 1/2 (2.10 m/s²) <em>t</em>²
and car B's position is given by
<em>x</em> = 300 m + (27.0 m/s) <em>t</em>
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Car A overtakes car B at the moment their positions are equal:
(20.0 m/s) <em>t</em> + 1/2 (2.10 m/s²) <em>t</em>² = 300 m + (27.0 m/s) <em>t</em>
300 m + (7.00 m/s) <em>t</em> - (1.05 m/s²) <em>t</em>² = 0
==> <em>t</em> ≈ 20.6 s