Exam 4: Motion in Two and Three Dimensions

A ball is connected by two massless strings to a horizontal, rotating rod, and moves in a vertical circle. The strings are tied to the rod, are taut, and form two sides of an equilateral triangle. A photograph of the system is taken at moment t and is shown in the figure here. At t the centripetal acceleration of the ball is

An arrow is shot into the air. While in the air, the arrow's acceleration is due to

At a certain instant, a car's velocity points northward. Its acceleration

Two projectiles, A and B, are launched with equal initial speeds. Projectile A is launched at angle 35° and projectile B at angle 55° above the horizontal. Which projectile reaches the ground first?

A boat is trying to cross a river that flows due north with a strong current. The boat starts at point A on the west bank and will reach the east bank directly across from the starting point. The boat should head

Two projectiles, A and B, are launched with the same speed from a tower. Projectile A is launched at an angle of 30° above the horizontal, and projectile B at an angle of 30° below the horizontal. Just before their impact point

A yellow ball rolling rapidly along a tabletop rolls off the edge and falls to the floor. At the same instant, a blue ball having the same mass and shape as the yellow one is dropped from the same height. The ball that reaches the floor first is

A train travels around a curve of increasing radius at a constant speed. The magnitude of the train's centripetal acceleration

A ball is thrown at an original speed of 6.0 m/s at an angle of 30^o above the horizontal. The speed of the ball when it returns to the same horizontal level is

For the two-dimensional motion of a projectile, all of the following apply except