Question 1

You throw a rock horizontally off a cliff with a speed of 20 m/s and no significant air resistance. After 2.0 s, the magnitude of the velocity of the rock is closest to

Accepted Answer

A)  28 m/s 
B)  20 m/s 
C)  40 m/s 
D)  37 m/s

Question 2

Mary and Debra stand on a snow-covered roof. They both throw snowballs with the same initial speed, but in different directions. Mary throws her snowball downward, at 30° below the horizontal; Debra throws her snowball upward, at 30° above the horizontal. Which of the following statements are true about just before the snowballs reach the ground below? (There could be more than one correct choice.)

Accepted Answer

A)  Debra's snowball will stay in the air longer than Mary's snowball. 
B)  Mary's snowball will stay in the air longer than Debra's snowball. 
C)  Both snowballs will take the same amount of time to hit the ground. 
D)  Debra's snowball has exactly the same acceleration as Mary's snowball. 
E)  Mary's snowball has a greater downward acceleration than Debra's snowball.

Question 3

Vector $\vec { A }$ is along the +x-axis and vector $\overrightarrow { \mathbf { B } }$ is along the +y-axis. Which one of the following statements is correct with respect to these vectors?

Accepted Answer

A)  The x component of vector $\vec { A }$ is equal to the x component of vector $\overrightarrow { \mathbf { B } }$ . 
B)  The y component of vector $\vec { A }$ is equal to the y component of vector $\overrightarrow { \mathbf { B } }$ . 
C)  The x component of vector $\vec { A }$ is equal to the y component of vector $\overrightarrow { \mathbf { B } }$ . 
D)  The y component of vector $\vec { A }$ is equal to the x component of vector $\overrightarrow { \mathbf { B } }$ .

Question 4

An athlete participates in an interplanetary discus throw competition during an Olympiad that takes place on a planet where the acceleration due to gravity is 9.7 m/s2. He throws the discus with an initial velocity of 20 m/s at an angle of 60° from the vertical. Neglecting air resistance and the height of the discus at the point of release, what is the range of the discus?

Accepted Answer

A)  21 m 
B)  60 m 
C)  36 m 
D)  40 m 
E)  32 m

Question 5

A vector in the xy-plane has an x component of -7.50 units. What must be the y component of this vector so that its magnitude is 10.0 units. (Note: There are two possible answers.)

Accepted Answer

The answer of A vector in the xy-plane has an...

Question 6

A disk-shaped space station 125 m in diameter spins at a uniform rate about an axis through its center and perpendicular to the plane of the disk. If the acceleration of a point on the rim of the disk is to be equal to g, how long does it take for the station to make one revolution? Use g = 9.8 m/s².

Accepted Answer

The answer of A disk-shaped space station 125 m in...

Question 7

A player hits a tennis ball into the air with an initial velocity of 32 m/s at 35° from the vertical. How fast is the ball moving at the highest point in its trajectory if air resistance is negligible?

Accepted Answer

The answer of A player hits a tennis ball into...

Question 8

A jet plane flying 600 m/s experiences an acceleration of 4.0 g when pulling out of the circular section of a dive. What is the radius of curvature of this section of the dive?

Accepted Answer

A)  1.2 km 
B)  5.8 km 
C)  0.64 km 
D)  9.2 km 
E)  7.0 km

Question 9

A child throws a ball with an initial speed of 8.0 m/s at an angle of 40° above the horizontal. The ball leaves her hand 1.0 m above the ground. At what angle below the horizontal does the ball approach the ground?

Accepted Answer

A)  35° 
B)  42° 
C)  48° 
D)  40° 
E)  65°

Question 10

You walk 53 m to the north, then you turn 60° to your right and walk another $45 \mathrm {~m} .$ Determine the direction of your displacement vector. Express your answer as an angle relative to east.

Accepted Answer

A)  63° N of E 
B)  50° N of E 
C)  57° N of E 
D)  69° N of E

Question 11

A plane flies directly from city A to city B, which are separated by 2300 mi. From A to B, the plane flies into a 65 mi/h headwind. On the return trip from B to A, the wind velocity is unchanged. The trip from B to A takes $65 \mathrm {~min}$ less than the trip from A to B. What is the airspeed (assumed constant) of the plane relative to the air (that is, the airspeed)?

Accepted Answer

A)  530 mi/h 
B)  400 mi/h 
C)  480 mi/h 
D)  610 mi/h

Question 12

The x component of vector $\vec { A }$ is 5.3 units, and its y component is -2.3 units. The angle that vector $\vec { A }$ makes with the +x-axis is closest to

Accepted Answer

A)  340° 
B)  160° 
C)  250° 
D)  110° 
E)  23°

Question 13

A ball is thrown with an initial velocity of 20 m/s at an angle of 60° above the horizontal. If we can neglect air resistance, what is the horizontal component of its instantaneous velocity at the exact top of its trajectory?

Accepted Answer

A)  10 m/s 
B)  17 m/s 
C)  20 m/s 
D)  zero

Question 14

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?

Accepted Answer

A)  100 m 
B)  160 m 
C)  180 m 
D)  320 m

Question 15

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.

Accepted Answer

A)  21 m/s 
B)  22 m/s 
C)  24 m/s 
D)  25 m/s 
E)  6.3 m/s

Question 16

A girl throws a rock horizontally with a speed of 12 m/s from a bridge. It falls 2.28 s before hitting the water below. Neglect air resistance.
(a) How high is the bridge from the water below?
(b) How far horizontally does the rock travel before striking the water?

Accepted Answer

The answer of A girl throws a rock horizontally with...

Question 17

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

Accepted Answer

A)  is always zero. 
B)  remains a non-zero constant. 
C)  continuously increases. 
D)  continuously decreases. 
E)  first decreases and then increases.

Question 18

A projectile is fired from ground level with a speed of 150 m/s at an angle 30° above the horizontal on an airless planet where g = 10.0 m/s2. What is the horizontal component of its velocity after 4.0 s?

Accepted Answer

A)  150 m/s 
B)  35 m/s 
C)  130 m/s 
D)  75 m/s 
E)  38 m/s

Question 19

When Jeff ran up a hill at 7.0 m/s, the horizontal component of his velocity vector was 5.1 m/s. What was the vertical component of Jeff's velocity?

Accepted Answer

A)  4.8 m/s 
B)  4.3 m/s 
C)  3.8 m/s 
D)  3.4 m/s

Question 20

The eastward component of vector $\vec { A }$ is equal to the westward component of vector $\overrightarrow { \mathbf { B } }$ and their northward components are equal. Which one of the following statements must be correct for these two vectors?

Accepted Answer

A)  Vector $\vec { A }$ is parallel to vector$\overrightarrow { \mathbf { B } }$ . 
B)  Vector $\vec { A }$ is antiparallel (in the opposite direction) to vector $\overrightarrow { \mathbf { B } }$ . 
C)  Vector $\vec { A }$ must be perpendicular to vector $\overrightarrow { \mathbf { B } }$ . 
D)  The magnitude of vector $\vec { A }$ must be equal to the magnitude of vector $\overrightarrow { \mathbf { B } }$ . 
E)  The angle between vector $\vec { A }$ and vector $\overrightarrow { \mathbf { B } }$ must be 90°.

Exam 3: Vectors and Motion in Two Dimensions

You throw a rock horizontally off a cliff with a speed of 20 m/s and no significant air resistance. After 2.0 s, the magnitude of the velocity of the rock is closest to

Vector $\vec { A }$ is along the +x-axis and vector $\overrightarrow { \mathbf { B } }$ is along the +y-axis. Which one of the following statements is correct with respect to these vectors?

A vector in the xy-plane has an x component of -7.50 units. What must be the y component of this vector so that its magnitude is 10.0 units. (Note: There are two possible answers.)

A player hits a tennis ball into the air with an initial velocity of 32 m/s at 35° from the vertical. How fast is the ball moving at the highest point in its trajectory if air resistance is negligible?

A jet plane flying 600 m/s experiences an acceleration of 4.0 g when pulling out of the circular section of a dive. What is the radius of curvature of this section of the dive?

A child throws a ball with an initial speed of 8.0 m/s at an angle of 40° above the horizontal. The ball leaves her hand 1.0 m above the ground. At what angle below the horizontal does the ball approach the ground?

You walk 53 m to the north, then you turn 60° to your right and walk another $45 \mathrm {~m} .$ Determine the direction of your displacement vector. Express your answer as an angle relative to east.

The x component of vector $\vec { A }$ is 5.3 units, and its y component is -2.3 units. The angle that vector $\vec { A }$ makes with the +x-axis is closest to

A ball is thrown with an initial velocity of 20 m/s at an angle of 60° above the horizontal. If we can neglect air resistance, what is the horizontal component of its instantaneous velocity at the exact top of its trajectory?

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?

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.

A girl throws a rock horizontally with a speed of 12 m/s from a bridge. It falls 2.28 s before hitting the water below. Neglect air resistance. (a) How high is the bridge from the water below? (b) How far horizontally does the rock travel before striking the water?

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

A projectile is fired from ground level with a speed of 150 m/s at an angle 30° above the horizontal on an airless planet where g = 10.0 m/s². What is the horizontal component of its velocity after 4.0 s?

When Jeff ran up a hill at 7.0 m/s, the horizontal component of his velocity vector was 5.1 m/s. What was the vertical component of Jeff's velocity?

The eastward component of vector $\vec { A }$ is equal to the westward component of vector $\overrightarrow { \mathbf { B } }$ and their northward components are equal. Which one of the following statements must be correct for these two vectors?

Exam 3: Vectors and Motion in Two Dimensions

You throw a rock horizontally off a cliff with a speed of 20 m/s and no significant air resistance. After 2.0 s, the magnitude of the velocity of the rock is closest to

Vector A⃗\vec { A }A is along the +x-axis and vector B→\overrightarrow { \mathbf { B } }B is along the +y-axis. Which one of the following statements is correct with respect to these vectors?

A vector in the xy-plane has an x component of -7.50 units. What must be the y component of this vector so that its magnitude is 10.0 units. (Note: There are two possible answers.)

A player hits a tennis ball into the air with an initial velocity of 32 m/s at 35° from the vertical. How fast is the ball moving at the highest point in its trajectory if air resistance is negligible?

A jet plane flying 600 m/s experiences an acceleration of 4.0 g when pulling out of the circular section of a dive. What is the radius of curvature of this section of the dive?

A child throws a ball with an initial speed of 8.0 m/s at an angle of 40° above the horizontal. The ball leaves her hand 1.0 m above the ground. At what angle below the horizontal does the ball approach the ground?

You walk 53 m to the north, then you turn 60° to your right and walk another 45 m.45 \mathrm {~m} .45 m. Determine the direction of your displacement vector. Express your answer as an angle relative to east.

The x component of vector A⃗\vec { A }A is 5.3 units, and its y component is -2.3 units. The angle that vector A⃗\vec { A }A makes with the +x-axis is closest to

A ball is thrown with an initial velocity of 20 m/s at an angle of 60° above the horizontal. If we can neglect air resistance, what is the horizontal component of its instantaneous velocity at the exact top of its trajectory?

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?

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.

A girl throws a rock horizontally with a speed of 12 m/s from a bridge. It falls 2.28 s before hitting the water below. Neglect air resistance. (a) How high is the bridge from the water below? (b) How far horizontally does the rock travel before striking the water?

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

A projectile is fired from ground level with a speed of 150 m/s at an angle 30° above the horizontal on an airless planet where g = 10.0 m/s2. What is the horizontal component of its velocity after 4.0 s?

When Jeff ran up a hill at 7.0 m/s, the horizontal component of his velocity vector was 5.1 m/s. What was the vertical component of Jeff's velocity?

The eastward component of vector A⃗\vec { A }A is equal to the westward component of vector B→\overrightarrow { \mathbf { B } }B and their northward components are equal. Which one of the following statements must be correct for these two vectors?

Vector $\vec { A }$ is along the +x-axis and vector $\overrightarrow { \mathbf { B } }$ is along the +y-axis. Which one of the following statements is correct with respect to these vectors?

You walk 53 m to the north, then you turn 60° to your right and walk another $45 \mathrm {~m} .$ Determine the direction of your displacement vector. Express your answer as an angle relative to east.

The x component of vector $\vec { A }$ is 5.3 units, and its y component is -2.3 units. The angle that vector $\vec { A }$ makes with the +x-axis is closest to

A projectile is fired from ground level with a speed of 150 m/s at an angle 30° above the horizontal on an airless planet where g = 10.0 m/s². What is the horizontal component of its velocity after 4.0 s?

The eastward component of vector $\vec { A }$ is equal to the westward component of vector $\overrightarrow { \mathbf { B } }$ and their northward components are equal. Which one of the following statements must be correct for these two vectors?