Physics Chapter 4

8.0 m/s

A ball is thrown at an original speed of 8.0 m/s at an angle of 35 degrees above the horizontal. What is the speed of the ball when it returns to the same horizontal level?

8.1 m/s

A ball thrown horizontally from a point 24 m above the ground, strikes the ground after traveling horizontally a distance of 18 m. With what speed was it thrown, assuming negligible air resistance?

9.8 m/s^2

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

20 m

A girl throws a rock horizontally, with a velocity of 10 m/s, from a bridge. It falls 20 m to the water below. How far does the rock travel horizontally before striking the water, assuming negligible air resistance?

be directly over the package

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

0 m/s^2

A projectile is launched with an initial velocity of 80 m/s at 30 degrees above the horizontal. Neglecting air resistance, what is the horizontal component of the projectile's acceleration?

91 m

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?

is always zero

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

remains a non-zero constant

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

remains a non-zero constant

For general projectile motion with no air resistance, the vertical component of a projectile's acceleration

parallel to each other (in the same direction)

If vector A + vector B = vector C and their magnitudes are given by A + B = C, then the vectors A and B are oriented

true

If vector A - vector B = 0, then the vectors A and B have equal magnitudes and are directed in the same direction- true or false

90 degrees to 180 degrees

If vector A has components Ax < 0, and Ay > 0, then the angle that this vector makes with the positive x-axis must be in the range

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

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.

true

The magnitude of a vector can never be less than the magnitude of any of its components- true or false

true

The magnitude of a vector can only be zero if all of its components are zero- true or false

340 degrees

The x component of Vector A is 5.3 units, and its y component is -2.3 units. The angle that Vector A makes with the +x-axis is closest to

could be as small as 2.0 m or as large as 12 m

Two displacement vectors have magnitudes of 5.0 m and 7.0 m, respectively. If these two vectors are added together, the magnitude of the sum

the y component of Vector A is equal to the x component of Vector B

Vector A is along the +x-axis and Vector B is along the +y-axis. Which one of the following statements is correct with respect to these vectors?

4.8 m/s

When Jeff ran up a hill at 7.0 m/s, the horizontal component of his velocity vector was 1.5 m/s. What was the vertical component of Jeff's velocity?

75 degrees

When rolled down a mountainside at 7.0 m/s, the horizontal component of its velocity vector was 1.8 m/s. What was the angle of the mountain surface above the horizontal?

in a general northwesterly direction

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

false

if a vector pointing upward has a positive magnitude, a vector pointing downward has a negative magnitude- true or false