Practice important
Horizontal Velocity
MCQ questions and answers.
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MCQ Questions
1. In ideal projectile motion, what happens to the horizontal component of velocity when air resistance is neglected?
A.
It remains constant
B.
It continuously increases
C.
It continuously decreases
D.
It becomes zero at the highest point
Correct Answer:
It remains constant
Explanation:
With air resistance neglected, there is no horizontal acceleration, so the horizontal velocity remains constant throughout the motion.
2. A projectile is launched with speed u at an angle θ to the horizontal. What is its initial horizontal velocity?
A.
u sin θ
B.
u cos θ
C.
u tan θ
D.
u
Correct Answer:
u cos θ
Explanation:
The horizontal component of the initial velocity is obtained by resolving the velocity vector along the horizontal direction: vx = u cos θ.
3. A ball is projected horizontally with a speed of 10 m/s. What is its horizontal velocity after 2 seconds, neglecting air resistance?
A.
0 m/s
B.
5 m/s
C.
10 m/s
D.
20 m/s
Correct Answer:
10 m/s
Explanation:
The horizontal velocity does not change during ideal projectile motion, so it remains 10 m/s after 2 seconds.
4. What is the horizontal acceleration of a projectile when air resistance is ignored?
A.
0 m/s²
B.
9.8 m/s²
C.
−9.8 m/s²
D.
1 m/s²
Correct Answer:
0 m/s²
Explanation:
Gravity acts vertically downward and provides no horizontal acceleration. Therefore, the horizontal acceleration is zero.
5. A projectile is launched at 60° with a speed of 20 m/s. What is its horizontal velocity? Use cos 60° = 0.5.
A.
5 m/s
B.
10 m/s
C.
17.3 m/s
D.
20 m/s
Correct Answer:
10 m/s
Explanation:
The horizontal velocity is vx = u cos θ = 20 × 0.5 = 10 m/s.
6. At the highest point of its path, what happens to the horizontal velocity of a projectile launched obliquely?
A.
It becomes zero
B.
It becomes twice its initial value
C.
It remains equal to its initial horizontal velocity
D.
It changes direction horizontally
Correct Answer:
It remains equal to its initial horizontal velocity
Explanation:
Since there is no horizontal acceleration, the horizontal velocity remains unchanged even at the highest point.
7. A projectile is fired at an angle of 0° with a speed of 15 m/s. What is its horizontal velocity?
A.
0 m/s
B.
7.5 m/s
C.
15 m/s
D.
30 m/s
Correct Answer:
15 m/s
Explanation:
For θ = 0°, the horizontal velocity is u cos 0° = u, so it is 15 m/s.
8. Which factor determines the initial horizontal velocity of a projectile?
A.
Only the gravitational acceleration
B.
The initial speed and the projection angle
C.
Only the time of flight
D.
Only the maximum height
Correct Answer:
The initial speed and the projection angle
Explanation:
The initial horizontal velocity is given by vx = u cos θ, so it depends on the initial speed u and the projection angle θ.
9. A projectile has an initial speed of 12 m/s and is launched at 90° to the horizontal. What is its initial horizontal velocity?
A.
0 m/s
B.
6 m/s
C.
12 m/s
D.
24 m/s
Correct Answer:
0 m/s
Explanation:
The horizontal component is vx = u cos 90° = 0, so the initial horizontal velocity is zero.
10. The horizontal velocity of a projectile is 8 m/s at the instant it is launched. What is its horizontal velocity 3 seconds later, neglecting air resistance?
A.
0 m/s
B.
8 m/s
C.
11 m/s
D.
24 m/s
Correct Answer:
8 m/s
Explanation:
Because the horizontal acceleration is zero, the horizontal velocity remains constant at 8 m/s.