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A ball attached to a string is whirled around in a horizontal circle having a radius r. If the radius of the circle is changed to 4r and the same centripetal force is applied by the string, the new speed of the ball is which of the following?

One-quarter the original speed

The same as the original speed

One-half the original speed

Four times the original speed

Twice the original speed

Two cars go around a banked curve at the proper speed for the banking angle. One car has tires with excellent traction, while the other car has bald slippery tires. Which of these cars is more likely to slide on the pavement as it goes around the curve?

Neither car will slide

The car with new tires

It depends on if the pavement is wet or dry

The car with the bald tires

8.5 x 103 N

5.8 x 10-8 N

What is the gravitational force acting on a 59-kg person due to another 59-kg person standing 2.0 m away? We can model each person as a small sphere.

1.2 x 10-7 N

9.8 x 10-10 N

2.0 x 10-9 N

Pulling out of a dive, the pilot of an airplane guides his plane into a vertical circle with a radius of 600m. At the bottom of the dive, the speed of the airplane is 150 m/s. What is the apparent weight of the 70-kg pilot at that point?

2600 N

690 N

3300 N

1400 N

490 N

The horizontal turntable shown above rotates at a constant rate. As viewed from above, a coin on the turntable moves counterclockwise in a circle as shown.

Which of the following vectors best represents the direction of the frictional force exerted on the coin by the turntable when the coin is in the position shown?