Motion in Two Dimensions

a force directed toward the center of a circle

• centripetal force

• frictional force

• gravitational force

• tension force

the movement of an object at a constant speed around a circle with a fixed radius

• trajectory

• centripetal acceleration

• centripetal force

• uniform circular motion

acceleration that always points toward the center of a circle

• centripetal acceleration

• linear acceleration

• angular acceleration

• gravitational acceleration

The motion of a projectile in terms of horizontal and vertical vectors involves:

• Horizontal vector changes, vertical vector remains constant

• Horizontal vector remains constant, vertical vector changes

• Both vectors change

• Both vectors remain constant

Two rocks are thrown from a cliff. One is thrown horizontally at a speed of 25 m/s. The other is dropped straight down. Which stone will hit the ground first? Why?

• The rock thrown horizontally will hit the ground first because it has an initial horizontal velocity.

• The rock dropped straight down will hit the ground first because it has no horizontal velocity.

• Both rocks will hit the ground at the same time because they are subject to the same gravitational acceleration.

A jet drops a bomb from an altitude of 3200 m. How long does it take for the bomb to hit the target on Earth, assuming air resistance is negligible?

• Approximately 41.6 seconds

• Approximately 25.6 seconds

• Approximately 326.5

• Approximately 54 seconds

What is the vertical component of the bomb's velocity dropped from 3200 m when it hits the ground? Assume that air resistance is negligible.

• 9.8 m/s

• 410 m/s

• 20 m/s

• 250 m/s

If the jet is traveling with a horizontal speed of 545 km/h when the bomb is released, what is the horizontal distance between the point at which the bomb is dropped and the point at which the bomb hits the target on the ground if oit took 25.6 seconds to hit and fell at 250 m/s?

• 545 meters

• 2000 meters

• 6400 meters

• 13080 meters

What are the two conditions necessary for an object to be in uniform circular motion?

• The object must have a constant speed and a constant radius of motion.

• The object must have a constant speed and a changing radius of motion.

• The object must have a changing speed and a constant radius of motion.

• The object must have a changing speed and a changing radius of motion.

A particle in uniform circular motion is not moving at a constant velocity because:

• its speed is changing.

• its direction is changing.

• it is accelerating towards the center.

• it is moving in a straight line.