Multiple Guess
Identify the choice that best completes the statement or answers the question.

____	1.	A stone is thrown horizontally from the top of a 25.00-m cliff. The stone lands at a distance of 40.00 m from the edge of the cliff. What is the initial horizontal velocity of the stone?
a.	2.260 m/s	c.	17.70 m/s	
b.	15.60 m/s	d.	22.05 m/s	

____	2.	A missile launches at a velocity of 30.0 m/s at an angle of 30.0° to the normal. What is the maximum height the missile attains?
a.	11.5 m	c.	34.4 m	
b.	27.5 m	d.	45.9 m	

____	3.	A sprinter runs at a speed of 3.00 m/s on a circular track that has a radius of 40.00 m. Find the centripetal acceleration of the sprinter.
a.	0.225 m/s2	c.	0.750 m/s2	
b.	4.44 m/s2	d.	0.0750 m/s2	

____	4.	A 0.50-kg ball is attached to a string of 0.50 m and swung in a horizontal circle with a velocity of 1.0 m/s. Find the centripetal force of the ball.
a.	0.50 N	c.	2.0 N	
b.	1.0 N	d.	2.5 N	

____	5.	A 1.00-kg ball is attached to a string of 0.50 m and swung in a horizontal circle with a velocity of 2.00 m/s. Find the centripetal acceleration.
a.	0.25 m/s2	c.	4.0 m/s2	
b.	2.0 m/s2	d.	8.0 m/s2	

	6.	An object in uniform circular motion moves at a constant speed around a circle with a fixed radius. Why is the object said to be accelerating though it has a constant speed?

	7.	A ball is tied to an elastic string of length 8.0 m and swung in a horizontal circle with a velocity of 0.8 m/s. When a metallic object is tied to a rope of length 2.75 m and swung in a horizontal circle, it makes one revolution in 2.9 s. The ratio of the centripetal force in the string to the centripetal force in the rope is . Find the mass of the metallic object attached to the rope, if the centripetal force in the string is 0.20 N.

	8.	A boat traveling east covers a distance of 40.0 m in 20.0 s. It encounters a current moving at a speed of 2.50 m/s traveling north. Find the resultant velocity of the boat.

	9.	A riverboat travels with a velocity of 4.60 m/s from one shore to another. The velocity of the river is 2.30 m/s. If the width of the river is 72.0 m, how far does the boat travel downstream to reach the other shore?

	10.	Two boats, A and B, travel with a velocity of 4.90 m/s across a river of width 72.0 m. The river flows with a velocity of 2.50 m/s. Boat A travels the shortest distance and boat B travels in the shortest time. If both start at the same time, how much time will they take to cross the river?

	11.	The Moon revolves around Earth in a circular orbit with a radius of 3.84´108 m. It takes 27.3 days for the Moon to complete one orbit around Earth. What is the centripetal acceleration of the Moon?

	12.	A 0.45-kg ball is attached to the end of a cord of length 1.4 m. The ball is whirled in a circular path in a horizontal plane. The cord can withstand a maximum tension of 57.0 N before it breaks. What is the maximum speed the ball can have without the cord breaking?

	13.	A town has a large clock on the hall in the town square. The clock has hands that show the hours, minutes, and seconds. A fly is sitting on the tip of the hand that shows the seconds. If the length of the hand is 1.20 m, what is the fly’s centripetal acceleration?

	14.	A rock is tied to a string and spun in a horizontal circle. The string is 1.8 m long and the rock has an acceleration of 3.4 m/s2. What is the tangential velocity of the rock?

	15.	A boy ties a 58-g tennis ball to the end of a light string that is 65 cm long and whirls the ball above his head in a horizontal circle, as shown at right. The boy exerts a force of 5.2 N on the string to keep the ball moving in a circle at a height of 1.7 m above the ground. Determine the speed of the ball.