Answer:
The beach ball's velocity at the moment it was tossed into the air is <u>4.9 m/s.</u>
Explanation:
Given:
Time taken by the ball to reach maximum height is, 
We know that, velocity of an object at the highest point is always zero. So, final velocity of the ball is, 
Also, acceleration acting on the ball is always due to gravity. So, acceleration of the ball is, 
The negative sign is used as acceleration is a vector and it acts in the downward direction.
Now, we have the equation of motion relating initial velocity, final velocity, acceleration and time given as:
Where, 'u' is the initial velocity.
Plug in the given values and solve for 'u'. This gives,
Therefore, the beach ball's velocity at the moment it was tossed into the air is 4.9 m/s
The victim's head is accelerated faster and harder than the
torso when the victom is involved in a typical rear-end collision.
The traffic accident where a vehicle crashes into another
vehicle that is directly in front of it is called a rear-end collision.
One of the most common accident in the United States is the
rear-end collision, and in a lot of cases, rear-end collisions are prompted by
drivers who are inattentive, unfavorable conditions of the road, and poor
following distance.
<span>An enough room in front of your car so you can stop when the
car in front of you stops suddenly is one basic driving rule. The person isn’t
driving safely if he / she is behind you and couldn’t stop.</span>
Answer: Elastic Potential Energy
Explanation: Energy present on compressed strings is called Elastic Potential Energy.
The change in potential energy when the block falls to ground is -480J.
The maximum change in kinetic energy of the ball is 480 J.
The initial kinetic energy of the ball is 0 J.
The final kinetic energy of the ball is 0.148J.
The initial potential energy of the ball is 0.187 J.
The final potential energy of the ball is 0 J.
The work done by the air resistance is 0.039 J.
<h3>Change in potential energy when the block falls to ground</h3>
ΔP.E = -mgh
ΔP.E = -Wh
ΔP.E = - 40 x 12
ΔP.E = -480 J
<h3>Maximum change in kinetic energy of the ball</h3>
ΔK.E = - ΔP.E
ΔK.E = - (-480 J)
ΔK.E = 480 J
<h3>Initial kinetic energy of the ball</h3>
K.Ei = 0.5mv²
where;
- v is zero since it is initially at rest
K.Ei = 0.5m(0) = 0
<h3>Final kinetic energy</h3>
K.Ef = 0.5mv²
K.Ef = 0.5(0.0091)(5.7)²
K.Ef = 0.148 J
<h3>Initial potential energy of the ball</h3>
P.Ei = mghi
P.Ei = 0.0091 x 9.8 x 2.1
P.Ei = 0.187 J
<h3>Final potential energy</h3>
P.Ef = mghf
P.Ef = 0.0091 x 9.8 x 0
P.Ef = 0
<h3>Work done by the air resistance</h3>
W = ΔE
W = P.E - K.E
W = 0.187 J - 0.148 J
W = 0.039 J
Learn more about potential energy here: brainly.com/question/1242059
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