PHY M03

If a vector's components are all negative, then the magnitude of the vector is negative.

False

A plane flying horizontally at a speed of 50 m/s and at an elevation of 160 m drops a package, and 2.0 s later it drops a second package. How far apart will the two packages land on the ground if air resistance is negligible?

100 m

The components of vectors A and B are given as follows: What is the magnitude of the vector difference B - A ?

13

A boy jumps with a velocity of magnitude 20.0 m/s at an angle of 25.0° above the horizontal. What is the horizontal component of the boy's velocity?

18.1 m/s

The sum of two vectors of fixed magnitudes has its minimum magnitude when the angle between these vectors is

180°

Three vectors, , have the components shown in the table. What is the magnitude of the resultant of these three vectors?

2.00 m

A hockey puck slides off the edge of a platform with an initial velocity of 20 m/s horizontally. The height of the platform above the ground is 2.0 m. What is the magnitude of the velocity of the puck just before it touches the ground? You can neglect air resistance.

21 m/s

At a location where g = 9.80 m/s2, a projectile returns to its original height after 4.08 seconds, during which time it travels 76.2 meters horizontally. If air resistance can be neglected, what was the projectile's initial speed?

27.4 m/s

A projectile is fired from the edge of a cliff as shown in the figure. The initial velocity components are 940 m/s (horizontal) and 96 m/s (vertical). The projectile reaches maximum height at point P and then falls and strikes the ground at point Q. How high is point P above point Q, assuming no air resistance?

490 m

Vector A has a magnitude of 6.0 m and points 30° north of east. Vector B has a magnitude of 4.0 m and points 30° west of north. The resultant vector A + B is given by

7.2 m at an angle of 26° east of north.

A boy kicks a football with an initial velocity of 20 m/s at an angle of 25° above the horizontal. If we neglect air resistance, the magnitude of the acceleration of the ball while it is in flight is

9.8 m/s2

A stone is thrown horizontally with an initial speed of 10 m/s from the edge of a cliff. A stopwatch measures the stone's trajectory time from the top of the cliff to the bottom to be 4.3 s. What is the height of the cliff if air resistance is negligibly small?

91m

Consider two vectors A and B shown in the figure. The difference A - B is best illustrated by

Choice (b)

A 20-ton truck collides with a 1500-lb car. Which of the following statements must be true?

During the collision, the force on the truck is equal to the force on the car.

James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. Compare the time it takes each to reach the lake below if there is no air resistance.

James and John will reach the surface of the lake at the same time.

You are trying to cross a river that flows toward the south with a strong current. You start out in your motorboat on the east bank desiring to reach the west bank directly west from your starting point. You should head your motorboat

in a general northwesterly direction.

For general projectile motion with no air resistance, the horizontal component of a projectile's velocity

remains a non-zero constant.

You push on box G that is next to box H, causing both boxes to slide along the floor, as shown in the figure. The reaction force to your push is

the push of box G against you.