Question

Consider a father pushing a child on a playground merry-go-round. The system has a moment of inertia of 84.4 kg · m². The father exerts a force on the merry-go-round perpendicular to its 1.50 m radius to achieve a torque of 375 N · m.

(a) Calculate the rotational kinetic energy (in J) in the merry-go-round plus child when they have an angular velocity of 10.0 rpm.

___J

(b) Using energy considerations, find the number of revolutions the father will have to push to achieve this angular velocity starting from rest.

___revolutions

(c)

Again, using energy considerations, calculate the force (in N) the father must exert to stop the merry-go-round in seven revolutions.

___N

QUESTION 2 During a very quick stop, a car undergoes an acceleration of -7.05 m/s².

(a) What is the angular acceleration (in rad/s²) of its 0.310 m radius tires, assuming they do not slip on the pavement? (Indicate the direction with the sign of your answer. Assume the tires initially rotated in the positive direction.)

rad/s²

(b) How many revolutions do the tires make before coming to rest, given their initial angular velocity is 92.0 rad/s?

____revolutions

(c) How long (in s) does the car take to stop completely?

___ s

(d) What distance (in m) does the car travel in this time?

____ m

(e) What was the car's initial velocity (in m/s)? (Indicate the direction with the sign of your answer.)

___ m/s

PLEASE ANSWER ALL THE QUESTIONS DONT GIVE ANY WRONG ANSWERS THANKS FOR YOUR HELP !

Answer 1

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