Airtimes

1) An airplane flying at 115 m/s due east makes a gradual turn following a circular path to fly south. The turn takes 15 seconds to complete. What is the magnitude of the centripetal acceleration during the turn?
a. 12 m/s2
b. 9.8 m/s2
c. 0 m/s2
d. 6.9 m/s
e. 8.1 m/s2

2) Two cars are traveling at the same constant speed v. Car A is moving along a straight section of the road, while B is rounding a circular turn. Which statement is true about the acceleration of the cars?
a. The acceleration of both cars is zero, since they are traveling at a constant speed.
b. Car A is accelerating, but car B is not accelerating.
C. Car A is not accelerating, but car B is accelerating,
d. Both cars are accelerating.

3) What is the mass on Mercury of an object that weighs 784 N on the earth’s surface?
a. 80.0 kg
b. 48.0 kg
C.118 kg
d. 26.0 kg
e. Not enough information given.

1) ma = mv^2/r

a= v^2/r
a = 115^2 / r

find ‘r’ by figuring out how much it travelled (this will be a quarter of a circle since it makes a 90 degree turn).

d = 115 x 15
d = 1725m

C = 1725 x 4 (since its a quarter)
C = 6900m

now find ‘r’

C = 2pi*r
6900 = 2pi*r
r = 6900/2pi
r = 1098m

plug info back to a=v^2/r

a = 115^2 /1098
a = 12.04 m/s^2

2) C…constant speed on straight road = no accel and since B is in circular motion…direction always changes..therefore accel on car B.

3) you need to find the Fg on Mercury…then use F = mg

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