Physics

15) At what angle should a water-gun be aimed in order for the water to land with the greatest horizontal range

C) 45

8) Vector A= (1, 3). Vector B= (3, 0). Vector C=A + B. What is the magnitude of C? A) 3 B) 4 C) 5 D) 7

C) 5

21) A bullet is fired horizontally, and at the same instant a second bullet is dropped from the same height. Ignore air resistance. Compare the times of fall of the two bullets

C) They hit at the same time

14) If the acceleration of an object is always directed perpendicular to its velocity, A) the object is speeding up. B) the object is slowing down. C) the object is turning. D) this situation would not be physically possible.

C) the object is turning.

4) The resultant of two vectors is the smallest when the angle between them is A) 0°. B) 45°. C) 90°. D) 180°.

D) 180°.

22) A plane flying horizontally at a speed of 50.0 m/s and at an elevation of 160 m drops a package. Two seconds later it drops a second package. How far apart will the two packages land on the ground

A) 100

3) Which of the following is an accurate statement? A) A vector cannot have zero magnitude if one of its components is not zero. B) The magnitude of a vector can be less than the magnitude of one of its components. C) If the magnitude of vector A is less than the magnitude of vector B, then the x-component of A is less than the x component of B. D) The magnitude of a vector can be positive or negative.

A) A vector cannot have zero magnitude if one of its components is not zero.

2) Which of the following operations will not change a vector? A) Translate it parallel to itself. B) Rotate it. C) Multiply it by a constant factor. D) Add a constant vector to it.

A) Translate it parallel to itself

At target practice, a rifle bullet is fired at an angle of 30° below the horizontal with an initial velocity of 800 m/s from the top of a cliff 80 m high. How far from the base of the cliff does it strike the level ground below? A) 130 m B) 140 m C) 150 m D) 160 m E) 2000 m

B) 140 m

19) When a football in a field goal attempt reaches its maximum height, how does its speed compare to its initial speed

B) It is less than its initial speed

A pilot drops a bomb from a plane flying horizontally at a constant speed. Neglecting air resistance, when the bomb hits the ground the horizontal location of the plane will

B) be over the bomb

20) A stone is thrown horizontally from the top of a tower at the same instant a ball is dropped vertically. Which object is traveling faster when it hits the level ground below

B) the stone

17) You are throwing a ball for the second time. If the ball leaves your hand with twice the velocity it had on your first throw, its horizontal range R (compared to your first serve) would be A) 1.4 times as much. B) half as much. C) twice as much. D) four times as much.

D) four times as much.