Physics 011

Chapter 3: Kinematics in Two Dimensions; Vectors

MC#3A





 

 

1.

 

A car travels due east for a distance of 3 miles and then due north for an additional 4 miles before stopping. What is the shortest straight line distance between the starting and ending points of this trip?
 The correct answer: 5 mi

See Section 3-2

 

 

2.

 

A car travels due east for a distance of 3 miles and then due north for an additional 4 miles before stopping. What is the angle a of the shortest path relative to due north?
 The correct answer: a = arc tan 3/4

See Section 3-4

 

 

3.

 

A vector A makes an angle of 60 with the x axis of a Cartesian coordinate system. Which of the following statements is true of the indicated magnitudes?
 The correct answer: Ay is greater than Ax

See Section 3-4

 

 

4.

 

Force is a vector quantity measured in units of newtons, N. What must be the angle between two concurrently acting forces of 5 N and 3 N respectively if the resultant vector is 8 N?
The correct answer: 0

 

 

5.

 

Two forces, A and B, act concurrently on an object. Both vectors have the same magnitude of 10 N and act at right angles to each other. What is the closest estimate of their resultant?

 

 

6.

 

For which of the vector diagrams is it true that T1 + T2 = T3?
 The correct answer:

See Section 3-2

 

 

7.

 

For which of the vector diagrams is it true that T1 - T2 = T3?
The correct answer:

 

 

8.

 

For which of the vector diagrams is it true that T1 + T2 + T3 = 0?
 The correct answer:

See Section 3-2

 

 

9.

 

For which of the vector diagrams is it most obviously true that T1 + T2 + T3 0?
 The correct answer:

See Section 3-2

 

 

10.

 

For which of the vector diagrams is it true that T1 + T3 = - T2?
 The correct answer:

See Section 3-2

 

 

11.

 

For which of the vector diagrams is it true that |T1|2 + |T2|2 = T3|2?
 The correct answer:

See Section 3-2

 

 

12.

 

Which of the following sets of displacements, if they were oriented any way you wish, could not be made to yield a zero net displacement?
 The correct answer: (2 m, 4 m, 7 m)

See Section 3-2

 

 

13.

 

An airplane is flying in the presence of a 100 km/h wind directed due north. What must be the velocity and heading of the plane if it is to maintain a velocity of 500 km/h due east with respect to the ground?
The correct answer: 510 km/h 11 South of East

 

 

14.

 

A quarterback throws a football with a velocity of 7 m/s and an angle of 15 above the horizontal. How far away should the designated receiver be?
 The correct answer: 2.50 m

See Section 3-6

 

 

15.

 

What must be the minimum velocity of a projectile launched from ground level over a flat, horizontal if it is to strike a target 100 meters away?
Your answer: 19.6 m/s
The correct answer: 31.3 m/s

See Section 3-6

 

 

16.

 

An arrow is shot at an angle of 30 above the horizontal with a speed of 29.4 m/s. How long will it take for the arrow to strike the ground?
 The correct answer: 3 s

See Section 3-6

 

 

17.

 

At what angle should a projectile be fired in order for its range to be at maximum?
 The correct answer: 45

See Section 3-6

 

 

18.

 

A bomber is traveling due east with a velocity of 300 m/s when it releases a bomb. If the bomb takes 2.00 seconds to strike the ground, what was the range (horizontal distance) of the bomb's path?

 

 

19.

 

A bomber is flying with a velocity of 500 km/h at an altitude of 1960 meters when it drops a bomb. How long does it take for the bomb to hit the ground?
 The correct answer: 20 s

See Section 3-6

 

 

20.

 

A ball is thrown from the roof of a tall building with a horizontal velocity of 6.0 m/s. What is its speed after 3.0 seconds of flight?
 The correct answer: 30 m/s

See Section 3-6

 

 

21.

 

A projectile is fired at an angle above the horizontal. The air resistance is negligible. The initial horizontal velocity component is twice that of the initial vertical velocity component. The trajectory of the missle is best described as
The correct answer: parabolic.

See Section 3-6

 

 

22.

 

Which trajectory best describes a ball rolling down a curved ramp that ends at point P?


 The correct answer: C

See Section 3-5

 

 

23.

 

A cannon is placed on a flatcar of a train. The train is moving with a uniform speed 5.0 m/s when the cannon fires a ball vertically up at 10 m/s. Which vector best represents the velocity of the cannon ball as seen by a man standing on the ground?
The correct answer:

 

 

24.

 

A bullet is fired from a gun with a muzzle velocity of 300 m/s and at an angle of 30 above the horizontal. What is the magnitude of the vertical component of the muzzle velocity?

 

 

25.

 

Assume that the magnitude of the acceleration of gravity is exactly 10.0 m/s2 and that there is no friction with the air. A bored golfer standing on a flat, horizontal section of the golf course hits a small stone with his club so that the horizontal and vertical components of its velocity as it leaves the ground are 20.0 m/s and 15.0 m/s respectively.

When the stone is at the top of its trajectory, its speed is ___ m/s.
 The correct answer: 20

See Section 3-5

 

 

26.

 

Assume that the magnitude of the acceleration of gravity is exactly 10.0 m/s2 and that there is no friction with the air. A bored golfer standing on a flat, horizontal section of the golf course hits a small stone with his club so that the horizontal and vertical components of its velocity as it leaves the ground are 20.0 m/s and 15.0 m/s respectively.

When the stone is at the top of its trajectory, the magnitude of its acceleration is ___ m/s2.
 The correct answer: 10

See Section 3-5

 

 

27.

 

Assume that the magnitude of the acceleration of gravity is exactly 10.0 m/s2 and that there is no friction with the air. A bored golfer standing on a flat, horizontal section of the golf course hits a small stone with his club so that the horizontal and vertical components of its velocity as it leaves the ground are 20.0 m/s and 15.0 m/s respectively.

The time required for the stone to reach the highest point in its trajectory is ___ s.
The correct answer: 1.5

 

 

28.

 

Assume that the magnitude of the acceleration of gravity is exactly 10.0 m/s2 and that there is no friction with the air. A bored golfer standing on a flat, horizontal section of the golf course hits a small stone with his club so that the horizontal and vertical components of its velocity as it leaves the ground are 20.0 m/s and 15.0 m/s respectively.

The horizontal distance traveled by the stone before it hits the ground is ___ m.
 The correct answer: 60

See Section 3-5

 

 

29.

 

A projectile is launched from ground level with speed vo at an angle o above the horizontal.

If vo was increased slightly, the range of the projectile would ___.
 The correct answer: increase

See Section 3-5/3-6

 

 

30.

 

A projectile is launched from ground level with speed vo at an angle o above the horizontal.

If o was increased slightly, the time the projectile spends in the air before hitting the ground would ___.
 The correct answer: increase

See Section 3-5/3-6

 

 

31.

 

A projectile is launched from ground level with speed vo at an angle o above the horizontal.

If vo was increased slightly, the maximum height attained by the projectile would ___.
 The correct answer: increase

See Section 3-5/3-6

 

 

32.

 

A projectile is launched from ground level with speed vo at an angle o above the horizontal.

If o was decreased slightly, the range of the projectile would ___.
 The correct answer: increase, decrease, or remain constant depending on other information