Exam 4: Motion in Two and Three Dimensions

A stone is tied to a string and whirled at constant speed in a horizontal circle. The speed is then doubled without changing the length of the string. Afterward the magnitude of the acceleration of the stone is:

A Ferris wheel with a radius of 8.0m makes 1 revolution every 10 s. When he is at the top, essentially a diameter above the ground, he releases a ball. How far from the point on the ground directly under the release point does the ball land?

A girl wishes to swim across a river to a point directly opposite as shown. She can swim at 2 m/s in still water and the river is flowing at 1 m/s. At what angle $\theta$ with respect to the line joining the starting and finishing points should she swim?

An object is moving on a circular path of radius $\pi$ meters at a constant speed of 4.0 m/s. The time required for one revolution is:

A girl jogs around a horizontally circle with a constant speed. She travels one fourth of a revolution, a distance of 25 m along the circumference of the circle, in 5.0 s. The magnitude of her acceleration is:

Identical guns fire identical bullets horizontally at the same speed from the same height above level planes, one on the Earth and one on the Moon. Which of the following three statements is/are true? I. The horizontal distance traveled by the bullet is greater for the Moon. II) The flight time is less for the bullet on the Earth. III) The velocities of the bullets at impact are the same.

Which of the curves on the graph below best represents the verticle component v_y versus t for a projectile fired at an angle of 45 $\degree$ above the horizontal?

Which of the following is a scalar quantity?

A cannon fires a projectile as shown. The dashed line shows the trajectory in the absence of gravity; points MNOP correspond to the position of the projectiole at one second intervals. If g = 10 m/s², the lengths X,Y,Z are:

A stone thrown from the top of a tall building follows a path that is:

Two bodies are falling with negligible air resistance, side by side, above a horizontal plane. If one of the bodies is given an additional horizontal acceleration during its descent, it:

A boat is traveling upstream at 14 mph with respect to a river that is flowing at 6 mph (with respect to the ground). A man runs directly across the boat, from one side to the other, at 6 mph (with respect to the boat). The speed of the man with respect to the ground is:

A ball is thrown horizontally from the top of a 20-m high hill. It strikes the ground at an angle of 45 $\degree$ . With what speed was it thrown?

For a biological sample in a 1.0-m radius centrifuge to have a centripetal acceleration of 25g its speed must be:

A boat is able to move through still water at 20 m/s. It makes a round trip to a town 3.0 km upstream. If the river flows at 5 m/s, the time required for this round trip is:

A ferry boat is sailing at 12 km 30 $\degree$ W of N with respect to a river that is flowing at 6.0 km/h E. As observed from the shore, the ferry boat is sailing:

A toy racing moves with constant speed around the circle shown below. When it is at point A its coordinates are x = 0, y = 3m and its velocity is When it is at point B its velocity and acceleration are:

A projectile is fired over level ground with an initial velocity that has a vertical component of 20 m/s and a horizontal component of 30 m/s. Using g = 10 m/s², the distance from launching to landing points is:

The velocity of a projectile equals its initial velocity added to:

A stone is tied to a 0.50-m string and whirled at a constant speed of 4.0 m/s in a vertical circle. Its acceleration at the top of the circle is: