Vectors and Projectiles Conceptual MC Questions Pre-Lecture Quiz 03

A) same magnitude, but can be in any direction If two vectors are given such that A + B = 0, what can you say about the magnitude and direction of vectors A and B? A) same magnitude, but can be in any direction B) same magnitude, but must be in the same direction C) different magnitudes, but must be in the same direction D) same magnitude, but must be in opposite directions E) different magnitudes, but must be in opposite directions Pre-Lecture Quiz 03

A) they are perpendicular to each other Given that A + B = C, and that lAl 2 + lBl 2 = lCl 2, how are vectors A and B oriented with respect to each other? A) they are perpendicular to each other B) they are parallel and in the same direction C) they are parallel but in the opposite direction D) they are at 45° to each other E) they can be at any angle to each other Pre-Lecture Quiz 03

A) they are perpendicular to each other Given that A + B = C, and that lAl + lBl = lCl , how are vectors A and B oriented with respect to each other? A) they are perpendicular to each other B) they are parallel and in the same direction C) they are parallel but in the opposite direction D) they are at 45° to each other E) they can be at any angle to each other Pre-Lecture Quiz 03

B) it increases, but by less than double C) it does not change If each component of a vector is doubled, what happens to the angle of that vector? A) it doubles B) it increases, but by less than double C) it does not change D) it is reduced by half E) it decreases, but not as much as half Pre-Lecture Quiz 03

A certain vector has x and y components that are equal in magnitude A certain vector has x and y components that are equal in magnitude. Which of the following is a possible angle for this vector, in a standard x-y coordinate system? A) 30° B) 180° C) 90° D) 60° E) 45° Pre-Lecture Quiz 03

You are adding vectors of length 20 and 40 units You are adding vectors of length 20 and 40 units. What is the only possible resultant magnitude that you can obtain out of the following choices? A) 0 B) 18 C) 37 D) 64 E) 100 [CORRECT 5 ANSWER] Pre-Lecture Quiz 03

A) it depends on how fast the cart is moving A small cart is rolling at constant velocity on a flat track. It fires a ball straight up into the air as it moves. After it is fired, what happens to the ball? A) it depends on how fast the cart is moving B) it falls behind the cart C) it falls in front of the cart D) it falls right back into the cart E) it remains at rest [CORRECT 5 ANSWER] Pre-Lecture Quiz 03

A) it depends upon how much the track is tilted Now the cart is being pulled along a horizontal track by an external force (a weight hanging over the table edge) and accelerating. It fires a ball straight out of the cannon as it moves. After it is fired, what happens to the ball? A) it depends upon how much the track is tilted B) it falls behind the cart C) it falls in front of the cart D) it falls right back into the cart E) it remains at rest Pre-Lecture Quiz 03

A) it depends upon how much the track is tilted The same small cart is now rolling down an inclined track and accelerating. It fires a ball straight out of the cannon as it moves. After it is fired, what happens to the ball? A) it depends upon how much the track is tilted B) it falls behind the cart C) it falls in front of the cart D) it falls right back into the cart E) it remains at rest Pre-Lecture Quiz 03

A) quickly lag behind the plane while falling You drop a package from a plane flying at constant speed in a straight line. Without air resistance, the package will: A) quickly lag behind the plane while falling B) remain vertically under the plane while falling C) move ahead of the plane while falling D) not fall at all [CORRECT 5 ANSWER] Pre-Lecture Quiz 03

(C) they both hit at the same time From the same height (and at the same time), one ball is dropped and another ball is fired horizontally. Which one will hit the flat ground first? (A) the “dropped” ball (B) the “fired” ball (C) they both hit at the same time (D) it depends on how hard the ball was fired (E) it depends on the initial height [CORRECT 5 ANSWER] Pre-Lecture Quiz 03

C) neither – they both have the same velocity on impact From the same height (and at the same time), one ball is dropped and another ball is fired horizontally. Which ball has the greater velocity at ground level? A) the “dropped” ball B) the “fired” ball C) neither – they both have the same velocity on impact D) it depends on how hard the ball was thrown [CORRECT 5 ANSWER] Pre-Lecture Quiz 03

A) just after it is launched B) at the highest point in its flight A projectile is launched from the ground at an angle of 30o. At what point in its trajectory does this projectile have the least speed? A) just after it is launched B) at the highest point in its flight C) just before it hits the ground D) halfway between the ground and the highest point E) speed is always constant [CORRECT 5 ANSWER] Pre-Lecture Quiz 03

Which of the 3 punts has the longest hang time? D) all have the same hang time A B C h [CORRECT 5 ANSWER] Pre-Lecture Quiz 03

A battleship simultaneously fires two shells at two enemy submarines A battleship simultaneously fires two shells at two enemy submarines. The shells are launched with the same initial velocity. If the shells follow the trajectories shown, which submarine gets hit first ? A B C) both at the same time [CORRECT 5 ANSWER] Pre-Lecture Quiz 03

For a cannon on Earth, the cannonball would follow path B For a cannon on Earth, the cannonball would follow path B. Instead, if the same cannon were on the Moon, where g = 1.6 m/s2, which path would the cannonball take in the same situation? A B D C Pre-Lecture Quiz 03

The spring-loaded gun can launch projectiles at different angles with the same launch speed. At what angle should the projectile be launched in order to travel the greatest distance before landing? A) 15° B) 30° C) 45° D) 60° E) 75° Pre-Lecture Quiz 03

B) maybe – it depends on the speed of the shot C) no, it misses You are trying to hit a friend with a water balloon. He is sitting in the window of his dorm room directly across the street. You aim straight at him and shoot. Just when you shoot, he falls out of the window! Does the water balloon hit him? A) yes, it hits B) maybe – it depends on the speed of the shot C) no, it misses D) the shot is impossible E) not really sure [CORRECT 5 ANSWER] Assume that the shot does have enough speed to reach the dorm across the street. Pre-Lecture Quiz 03

B) maybe – it depends on the speed of the shot You’re on the street, trying to hit a friend with a water balloon. He sits in his dorm room window above your position. You aim straight at him and shoot. Just when you shoot, he falls out of the window! Does the water balloon hit him?? A) yes, it hits B) maybe – it depends on the speed of the shot C) the shot is impossible D) no, it misses E) not really sure [CORRECT 5 ANSWER] Assume that the shot does have enough speed to reach the dorm across the street. Pre-Lecture Quiz 03

B) maybe – it depends on the speeds of the shots You’re on the street, trying to hit a friend with a water balloon. He sits in his dorm room window above your position and is aiming at you with HIS water balloon! You aim straight at him and shoot and he does the same in the same instant. Do the water balloons hit each other? A) yes, they hit B) maybe – it depends on the speeds of the shots C) the shots are impossible D) no, they miss E) not really sure Pre-Lecture Quiz 03

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