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 during the flight?
A.
It continuously increases
B.
It continuously decreases
C.
It remains constant
D.
It becomes zero immediately
Correct Answer:
It remains constant
Explanation:
In ideal projectile motion, air resistance is neglected and there is no horizontal acceleration. Therefore, the horizontal velocity remains constant throughout the flight.
2. A projectile is launched with a horizontal velocity of 8 m/s. What is its horizontal velocity after 2 seconds, neglecting air resistance?
A.
0 m/s
B.
4 m/s
C.
8 m/s
D.
16 m/s
Correct Answer:
8 m/s
Explanation:
Since horizontal acceleration is zero in ideal projectile motion, the horizontal velocity remains equal to its initial value of 8 m/s.
3. A projectile is launched with speed u at an angle theta above the horizontal. Which expression gives its initial horizontal velocity?
A.
u sin theta
B.
u cos theta
C.
u tan theta
D.
u divided by cos theta
Correct Answer:
u cos theta
Explanation:
The horizontal component of the initial velocity is obtained by resolving the velocity vector along the horizontal direction, giving u cos theta.
4. At the highest point of its trajectory, the horizontal velocity of a projectile is:
A.
Zero
B.
Equal to its initial horizontal velocity
C.
Equal to its vertical velocity
D.
Greater than its initial horizontal velocity
Correct Answer:
Equal to its initial horizontal velocity
Explanation:
Gravity acts vertically, so it does not change the horizontal component of velocity. Thus, the horizontal velocity at the highest point equals its initial horizontal velocity.
5. A projectile is fired at an angle of 60 degrees with speed 20 m/s. What is its initial horizontal velocity?
A.
10 m/s
B.
20 m/s
C.
10√3 m/s
D.
20√3 m/s
Correct Answer:
10 m/s
Explanation:
The initial horizontal velocity is u cos theta = 20 cos 60 degrees = 20 × 1/2 = 10 m/s.
6. Why does the horizontal velocity of an ideal projectile remain constant?
A.
The vertical acceleration cancels the horizontal velocity
B.
There is no horizontal acceleration
C.
The projectile has no vertical velocity
D.
Gravity acts horizontally
Correct Answer:
There is no horizontal acceleration
Explanation:
In ideal projectile motion, gravity acts only in the vertical direction. Hence, horizontal acceleration is zero and horizontal velocity remains constant.
7. A ball rolls horizontally off a table with a speed of 5 m/s. What is its horizontal velocity just before reaching the ground, neglecting air resistance?
A.
0 m/s
B.
2.5 m/s
C.
5 m/s
D.
10 m/s
Correct Answer:
5 m/s
Explanation:
The ball has no horizontal acceleration after leaving the table, so its horizontal velocity remains 5 m/s.
8. If the initial horizontal velocity of a projectile is doubled, its horizontal velocity during the flight will:
A.
Become half
B.
Remain unchanged
C.
Also double
D.
Become zero
Correct Answer:
Also double
Explanation:
Because horizontal velocity remains constant during ideal projectile motion, doubling its initial horizontal value doubles its horizontal velocity at every later time.
9. A projectile has an initial speed of 10 m/s and is launched horizontally. What is its horizontal velocity throughout its motion, neglecting air resistance?
A.
0 m/s
B.
5 m/s
C.
10 m/s
D.
It increases with time
Correct Answer:
10 m/s
Explanation:
For a horizontally launched projectile, the initial velocity is entirely horizontal. Since there is no horizontal acceleration, the horizontal velocity remains 10 m/s.
10. Two projectiles are launched with the same initial horizontal velocity but different vertical velocities. Neglecting air resistance, their horizontal velocities during flight are:
A.
Different because their vertical velocities differ
B.
The same because their horizontal velocities are unchanged
C.
Zero for both projectiles
D.
Increasing for both projectiles
Correct Answer:
The same because their horizontal velocities are unchanged
Explanation:
The vertical component of motion does not affect the horizontal component. With the same initial horizontal velocity and zero horizontal acceleration, both projectiles have the same horizontal velocity.