Centripetal Force Problem Set
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1) A 25 kg child is sitting 1.1 m from the center of a merry go round moves with
a speed of 1.25 m/s.
a. Calculate the Centripetal Force needed to keep the child moving in a
circle.
b. What types of force contributes to the total centripetal force keeping
the child moving in a circle?
2) A 7000 kg Jet plane does a trick in which it turns in a horizontal circle. What
centripetal force does the air provide to the plane to keep it moving in a
circle if the plane is traveling with speed 525 m/s and is moving in a circle of
radius 6000 m.
3) A 2000 kg car turns in a loop of radius 15 m when entering a highway. The
car is traveling with speed 5 m/s around the loop.
a. Calculate the centripetal Force needed to keep the car in the turn.
b. If the turn was sharper, having a smaller radius of 5 m instead what
centripetal force would be needed to keep the car in the turn? Do cars
need more or less centripetal force to make sharp turns? Explain why.
c. If the car made the 15m radius loop with a faster speed of 10 m/s
instead what centripetal force would be needed to keep the car in the
turn? Do cars need more or less centripetal force to make turns
faster? Explain why.
d. What force keeps cars in a turn, if you do not have enough of this force
what happens to the car?
4) A 4000 kg truck turns in a loop of radius 10 m when making a turn. Friction
can provide the truck a force of 19600 N but no greater. What maximum
speed can the truck make the turn with?
5) On a playground carousel sally, 30 kg, wants to see how fast she can go
before friction allows her to slip off. She knows that she can be provided a
maximum friction force of 88 N. She sits at the edge of the carousel, which is
1.2 m from the center. What maximum speed can she get before she slips off?
6) A .1 kg ball on the end of a sting can be revolved in a horizontal circle. The
string is .5 m long and can hold a maximum tension of 130 N. What is the
maximum speed at which you can spin the object at the end of the string
without it snapping the string?
7) A 2300 kg car makes a turn at 15 m/s and is provided a friction force of
11270 N. What is the minimum radius at which the car can make the turn
safely?
Answers:
1) a. 34.375 N
2) a. 321,562.5 N
3) a. 3,333.33 N
b. 10,000 N
c. 13,333.33 N
4) 7 m/s
5) 1.87 m/s
6) 25.5 m/s
7) 45.92 m