Given:
m = 0.32 kg
v = 11.5 m/s
To find:
1) Kinetic energy = ?
2) Work needed to stop the ball = ?
Formula used:
1) Kinetic energy =
2) Work = kinetic energy
Solution:
1)
Kinetic energy is given by,
Kinetic energy =
K.E. =
K.E. = 21.16 Joule
Thus, option (d) is the correct answer.
2)
Work needed to stop the ball is same as the kinetic energy because energy is the capacity to do work. Since, work is opposing the movement of the ball. Thus, Work = - Kinetic energy
Work = -21.16 Joule
500 N is the answer, you just tell that the moon is attracted towards the person because of the Earth's huge mass.
The initial velocity of the hoop is determined as 8.854 m/s.
<h3>Conservation of energy</h3>
The initial velocity of the hoop can be determined from the principle of conservation of energy.
Final potential energy = Initial kinetic energy
P.E = K.E
mgh = ¹/₂mv²
gh = ¹/₂v²
2gh = v²
√2gh = v
√(2 x 9.8 x 4) = v
8.854 m/s = v
Thus, the initial velocity of the hoop is determined as 8.854 m/s.
Learn more about initial velocity here: brainly.com/question/19365526
#SPJ1