Circular Motion (Doug G7 Ch5 Conceptual)

You are making a circular turn in your car on a horizontal road when you hit a big patch of ice, causing the force of friction between the tires and the road to become zero. While the car is on the ice, it

• moves along a straight-line path away from the center of the circle.

• moves along a straight-line path toward the center of the circle.

• moves along a straight-line path in its original direction.

• continues to follow a circular path, but with a radius larger than the original radius.

• moves along a path that is neither straight nor circular.

When a car goes around a circular curve on a horizontal road at constant speed, what force causes it to follow the circular path?

• the normal force from the road

• the friction force from the road

• gravity

• No force causes the car to do this because the car is traveling at constant speed and therefore has no acceleration.

A car goes around a circular curve on a horizontal road at constant speed. What is the direction of the friction force on the car due to the road?

• tangent to the curve in the forward direction

• tangent to the curve opposite to the direction of the car's motion

• perpendicular to the curve outward

• perpendicular to the curve inward

• There is no friction on the car because its speed is constant.

When an object moves in uniform circular motion, the direction of its acceleration is

• in the same direction as its velocity vector.

• in the opposite direction of its velocity vector.

• directed toward the center of its circular path.

• directed away from the center of its circular path.

• depends on the speed of the object.

If you swing a bucket of water fast enough in a vertical circle, at the highest point the water does not spill out. This happens because an outward force balances the pull of gravity on the water.

• True

• False

When a car goes around a banked circular curve at the proper speed for the banking angle, what force causes it to follow the circular path?

• the normal force from the road

• the friction force from the road

• gravity

• No force causes the car to do this because the car is traveling at constant speed and therefore has no acceleration.

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?

• the car with the new tires

• the car with the bald tires

• Neither car will slide.

• It depends on if the pavement is wet or dry.

Two small balls, A and B, attract each other gravitationally with a force of magnitude F. If we now double both masses and the separation of the balls, what will now be the magnitude of the attractive force on each one?

• 16F

• 8F

• 4F

• F

• F/4

Two small objects, with masses m and M, are originally a distance r apart, and the magnitude of the gravitational force on each one is F. The masses are changed to 2m and 2M, and the distance is changed to 4r. What is the magnitude of the new gravitational force?

• F/16

• F/4

• 16F

• 4F

• F/2

Two small objects, with masses m and M, are originally a distance r apart, and the gravitational force on each one has magnitude F. The second object has its mass changed to 2M, and the distance is changed to r/4. What is the magnitude of the new gravitational force?

• F/32

• F/16

• 16F

• 32F

• 2F