Horizontal Projectile Motion MCQs
1. A projectile is fired horizontally from a height of 20 m with a velocity of 10 m/s. The time taken to reach the ground is: (Take \( g = 10 \, \text{m/s}^2 \))
a) 1 s
b) 2 s
c) 3 s
d) 4 s
Correct Answer: (b) 2 s
Time depends only on vertical motion: \[ h = \frac{1}{2} g t^2 \] \[ 20 = \frac{1}{2} \times 10 \times t^2 \] \[ t^2 = 4 \] \[ t = 2 \, \text{s} \]
2. A ball is projected horizontally with a velocity of 5 m/s from the top of a tower of height 45 m. Its horizontal range is: (Take \( g = 10 \, \text{m/s}^2 \))
a) 15 m
b) 20 m
c) 25 m
d) 30 m
Correct Answer: (a) 15 m
Time to reach ground: \[ h = \frac{1}{2} g t^2 \] \[ 45 = 5 t^2 \] \[ t = 3 \, \text{s} \] Range: \[ \text{Range} = v_x \times t = 5 \times 3 = 15 \, \text{m} \]
3. In horizontal projectile motion, the horizontal component of velocity:
a) Increases with time
b) Decreases with time
c) Remains constant
d) First increases then decreases
Correct Answer: (c) Remains constant
Since there is no horizontal acceleration (\( a_x = 0 \)), the horizontal component of velocity (\( v_x \)) remains constant throughout the motion.
4. A projectile is thrown horizontally from the top of a cliff. The trajectory of the projectile is a:
a) Straight line
b) Circle
c) Parabola
d) Hyperbola
Correct Answer: (c) Parabola
The path of a projectile (under constant gravity) is parabolic because: \[ y = \frac{g}{2v_x^2}x^2 \] This is the equation of a parabola.
5. A stone is projected horizontally from a tower. The speed of the stone just before hitting the ground is 50 m/s. If it was projected with 30 m/s, the height of the tower is: (Take \( g = 10 \, \text{m/s}^2 \))
a) 80 m
b) 100 m
c) 120 m
d) 160 m
Correct Answer: (a) 80 m
Final speed: \[ v = \sqrt{v_x^2 + v_y^2} \] \[ 50 = \sqrt{30^2 + v_y^2} \] \[ v_y = 40 \, \text{m/s} \] Time of flight: \[ v_y = g t \] \[ t = 4 \, \text{s} \] Height: \[ h = \frac{1}{2} g t^2 = \frac{1}{2} \times 10 \times 16 = 80 \, \text{m} \]
6. A projectile is fired horizontally from a height of 80 m. If its horizontal range is 60 m, the initial velocity is: (Take \( g = 10 \, \text{m/s}^2 \))
a) 10 m/s
b) 15 m/s
c) 20 m/s
d) 30 m/s
Correct Answer: (b) 15 m/s
Time to reach ground: \[ h = \frac{1}{2} g t^2 \] \[ 80 = 5 t^2 \] \[ t = 4 \, \text{s} \] Initial velocity: \[ \text{Range} = v_x \times t \] \[ 60 = v_x \times 4 \] \[ v_x = 15 \, \text{m/s} \]
7. The acceleration of a horizontally projected projectile at any point of its flight is:
a) Zero
b) \( g \) downward
c) Depends on initial velocity
d) Changes direction
Correct Answer: (b) \( g \) downward
The only acceleration in projectile motion is due to gravity (\( g \)) acting downward. This remains constant throughout the flight.
8. A bullet is fired horizontally from a rifle. Neglecting air resistance, the time taken to hit the ground depends on:
a) Mass of the bullet
b) Initial speed
c) Height from which it is fired
d) Both (a) and (b)
Correct Answer: (c) Height from which it is fired
Time of flight depends only on vertical height: \[ t = \sqrt{\frac{2h}{g}} \] It is independent of mass or horizontal speed.
9. Two balls are projected horizontally from the same height, one with velocity \( v \) and the other with \( 2v \). The ratio of their times of flight is:
a) 1:1
b) 1:2
c) 2:1
d) 1:4
Correct Answer: (a) 1:1
Time of flight depends only on height (same for both) and is independent of horizontal velocity. Therefore, the ratio is 1:1.
10. A projectile is fired horizontally from the top of a tower. The horizontal distance covered by the projectile when its vertical displacement is \( h \) is:
a) \( h \)
b) \( h \sqrt{2} \)
c) \( \sqrt{2gh} \)
d) \( v \sqrt{\frac{2h}{g}} \)
Correct Answer: (d) \( v \sqrt{\frac{2h}{g}} \)
Time taken for vertical displacement \( h \): \[ h = \frac{1}{2} g t^2 \] \[ t = \sqrt{\frac{2h}{g}} \] Horizontal distance: \[ \text{Distance} = v \times t = v \sqrt{\frac{2h}{g}} \]
Horizontal Projectile Motion MCQs
11. A projectile is fired horizontally from a height of 20 m with a velocity of 10 m/s. The time taken to reach the ground is: (Take \( g = 10 \, \text{m/s}^2 \))
a) 1 s
b) 2 s
c) 3 s
d) 4 s
Correct Answer: (b) 2 s
Time depends only on vertical motion: \[ h = \frac{1}{2} g t^2 \] \[ 20 = \frac{1}{2} \times 10 \times t^2 \] \[ t^2 = 4 \] \[ t = 2 \, \text{s} \]
12. A ball is projected horizontally with a velocity of 5 m/s from the top of a tower of height 45 m. Its horizontal range is: (Take \( g = 10 \, \text{m/s}^2 \))
a) 15 m
b) 20 m
c) 25 m
d) 30 m
Correct Answer: (a) 15 m
Time to reach ground: \[ h = \frac{1}{2} g t^2 \] \[ 45 = 5 t^2 \] \[ t = 3 \, \text{s} \] Range: \[ \text{Range} = v_x \times t = 5 \times 3 = 15 \, \text{m} \]
13. In horizontal projectile motion, the horizontal component of velocity:
a) Increases with time
b) Decreases with time
c) Remains constant
d) First increases then decreases
Correct Answer: (c) Remains constant
Since there is no horizontal acceleration (\( a_x = 0 \)), the horizontal component of velocity (\( v_x \)) remains constant throughout the motion.
14. A projectile is thrown horizontally from the top of a cliff. The trajectory of the projectile is a:
a) Straight line
b) Circle
c) Parabola
d) Hyperbola
Correct Answer: (c) Parabola
The path of a projectile (under constant gravity) is parabolic because: \[ y = \frac{g}{2v_x^2}x^2 \] This is the equation of a parabola.
15. A stone is projected horizontally from a tower. The speed of the stone just before hitting the ground is 50 m/s. If it was projected with 30 m/s, the height of the tower is: (Take \( g = 10 \, \text{m/s}^2 \))
a) 80 m
b) 100 m
c) 120 m
d) 160 m
Correct Answer: (a) 80 m
Final speed: \[ v = \sqrt{v_x^2 + v_y^2} \] \[ 50 = \sqrt{30^2 + v_y^2} \] \[ v_y = 40 \, \text{m/s} \] Time of flight: \[ v_y = g t \] \[ t = 4 \, \text{s} \] Height: \[ h = \frac{1}{2} g t^2 = \frac{1}{2} \times 10 \times 16 = 80 \, \text{m} \]
16. A projectile is fired horizontally from a height of 80 m. If its horizontal range is 60 m, the initial velocity is: (Take \( g = 10 \, \text{m/s}^2 \))
a) 10 m/s
b) 15 m/s
c) 20 m/s
d) 30 m/s
Correct Answer: (b) 15 m/s
Time to reach ground: \[ h = \frac{1}{2} g t^2 \] \[ 80 = 5 t^2 \] \[ t = 4 \, \text{s} \] Initial velocity: \[ \text{Range} = v_x \times t \] \[ 60 = v_x \times 4 \] \[ v_x = 15 \, \text{m/s} \]
17. The acceleration of a horizontally projected projectile at any point of its flight is:
a) Zero
b) \( g \) downward
c) Depends on initial velocity
d) Changes direction
Correct Answer: (b) \( g \) downward
The only acceleration in projectile motion is due to gravity (\( g \)) acting downward. This remains constant throughout the flight.
18. A bullet is fired horizontally from a rifle. Neglecting air resistance, the time taken to hit the ground depends on:
a) Mass of the bullet
b) Initial speed
c) Height from which it is fired
d) Both (a) and (b)
Correct Answer: (c) Height from which it is fired
Time of flight depends only on vertical height: \[ t = \sqrt{\frac{2h}{g}} \] It is independent of mass or horizontal speed.
19. Two balls are projected horizontally from the same height, one with velocity \( v \) and the other with \( 2v \). The ratio of their times of flight is:
a) 1:1
b) 1:2
c) 2:1
d) 1:4
Correct Answer: (a) 1:1
Time of flight depends only on height (same for both) and is independent of horizontal velocity. Therefore, the ratio is 1:1.
20. A projectile is fired horizontally from the top of a tower. The horizontal distance covered by the projectile when its vertical displacement is \( h \) is:
a) \( h \)
b) \( h \sqrt{2} \)
c) \( \sqrt{2gh} \)
d) \( v \sqrt{\frac{2h}{g}} \)
Correct Answer: (d) \( v \sqrt{\frac{2h}{g}} \)
Time taken for vertical displacement \( h \): \[ h = \frac{1}{2} g t^2 \] \[ t = \sqrt{\frac{2h}{g}} \] Horizontal distance: \[ \text{Distance} = v \times t = v \sqrt{\frac{2h}{g}} \]
Physics MCQs
21. A bomb is dropped from an aeroplane moving horizontally at constant speed. When air resistance is taken into consideration, the bomb
a) Falls to earth exactly below the aeroplane
b) Fall to earth behind the aeroplane
c) Falls to earth ahead of the aeroplane
d) Flies with the aeroplane
Correct answer: b) Fall to earth behind the aeroplane
When air resistance is considered, the horizontal velocity of the bomb decreases due to drag, while the aeroplane maintains its constant speed. Therefore, the bomb lags behind the aeroplane as it falls.
22. The maximum range of a gun on horizontal terrain is 16 km. If \( g = 10 \, m/s^2 \). What must be the muzzle velocity of the shell
a) 200 m/s
b) 400 m/s
c) 100 m/s
d) 50 m/s
Correct answer: b) 400 m/s
The maximum range \( R_{max} \) is given by: \[ R_{max} = \frac{v_0^2}{g} \] Given \( R_{max} = 16 \, km = 16000 \, m \) and \( g = 10 \, m/s^2 \): \[ 16000 = \frac{v_0^2}{10} \] \[ v_0^2 = 160000 \] \[ v_0 = 400 \, m/s \]
23. A bullet is dropped from the same height when another bullet is fired horizontally. They will hit the ground
a) One after the other
b) Simultaneously
c) Depends on the observer
d) None of the above
Correct answer: b) Simultaneously
Both bullets have the same initial vertical velocity (zero) and experience the same acceleration due to gravity. The horizontal motion doesn't affect the vertical fall time, so they hit the ground simultaneously.
24. An aeroplane is flying at a constant horizontal velocity of 600 km/hr at an elevation of 6 km towards a point directly above the target on the earth's surface. At an appropriate time, the pilot releases a ball so that it strikes the target at the earth. The ball will appear to be falling
a) On a parabolic path as seen by pilot in the plane
b) Vertically along a straight path as seen by an observer on the ground near the target
c) On a parabolic path as seen by an observer on the ground near the target
d) On a zig-zag path as seen by pilot in the plane
Correct answer: a) On a parabolic path as seen by pilot in the plane
From the pilot's frame of reference (moving with the plane), the ball appears to fall vertically downward. From the ground observer's perspective, it follows a parabolic trajectory due to the combination of horizontal and vertical motion.
25. At the height 80 m, an aeroplane is moving with 150 m/s. A bomb is dropped from it so as to hit a target. At what distance from the target should the bomb be dropped
a) 605.3 m
b) 600 m
c) 80 m
d) 230 m
Correct answer: a) 605.3 m
First calculate time to fall: \[ h = \frac{1}{2}gt^2 \] \[ 80 = \frac{1}{2} \times 9.8 \times t^2 \] \[ t = \sqrt{\frac{160}{9.8}} \approx 4.04 \, s \] Horizontal distance: \[ d = v \times t = 150 \times 4.04 \approx 605.3 \, m \]
26. An aeroplane moving horizontally with a speed of 720 km/h drops a food pocket, while flying at a height of 396.9 m. the time taken by a food pocket to reach the ground and its horizontal range is (Take \( g = 9.8 \, m/sec^2 \))
a) 3 sec and 2000 m
b) 5 sec and 500 m
c) 8 sec and 1500 m
d) 9 sec and 1800 m
Correct answer: d) 9 sec and 1800 m
Time to fall: \[ h = \frac{1}{2}gt^2 \] \[ 396.9 = \frac{1}{2} \times 9.8 \times t^2 \] \[ t^2 = \frac{793.8}{9.8} = 81 \] \[ t = 9 \, s \] Convert speed: \( 720 \, km/h = 200 \, m/s \) Horizontal range: \[ R = 200 \times 9 = 1800 \, m \]
27. An aeroplane flying 490 m above ground level at 100 m/s, releases a block. How far on ground will it strike
a) 0.1 km
b) 1 km
c) 2 km
d) None
Correct answer: b) 1 km
Time to fall: \[ h = \frac{1}{2}gt^2 \] \[ 490 = \frac{1}{2} \times 9.8 \times t^2 \] \[ t^2 = 100 \] \[ t = 10 \, s \] Horizontal distance: \[ d = 100 \times 10 = 1000 \, m = 1 \, km \]
28. A man projects a coin upwards from the gate of a uniformly moving train. The path of coin for the man will be
a) Parabolic
b) Inclined straight line
c) Vertical straight line
d) Horizontal straight line
Correct answer: c) Vertical straight line
In the man's frame of reference (moving with the train), the coin only has vertical motion. The horizontal motion of the train is shared by both the man and the coin, so the path appears vertical.
29. An aeroplane is flying horizontally with a velocity of 600 km/h at a height of 1960 m. When it is vertically at a point A on the ground, a bomb is released from it. The bomb strikes the ground at point B. The distance AB is
a) 1200 m
b) 0.33 km
c) 3.33 km
d) 33 km
Correct answer: c) 3.33 km
Time to fall: \[ h = \frac{1}{2}gt^2 \] \[ 1960 = \frac{1}{2} \times 9.8 \times t^2 \] \[ t^2 = 400 \] \[ t = 20 \, s \] Convert speed: \( 600 \, km/h = \frac{600 \times 1000}{3600} \approx 166.67 \, m/s \) Horizontal distance: \[ AB = 166.67 \times 20 \approx 3333.33 \, m \approx 3.33 \, km \]
30. A ball is rolled off the edge of a horizontal table at a speed of 4 m/second. It hits the ground after 0.4 second. Which statement given below is true
a) It hits the ground at a horizontal distance 1.6 m from the edge of the table
b) The speed with which it hits the ground is 4.0 m/second
c) Height of the table is 0.8 m
d) It hits the ground at an angle of 60° to the horizontal
Correct answer: c) Height of the table is 0.8 m
Calculate height: \[ h = \frac{1}{2}gt^2 = \frac{1}{2} \times 9.8 \times (0.4)^2 = 0.784 \, m \approx 0.8 \, m \] Horizontal distance is correct (1.6 m) but not listed as true. Final speed would be: \[ v_y = gt = 9.8 \times 0.4 = 3.92 \, m/s \] \[ v = \sqrt{4^2 + 3.92^2} \approx 5.6 \, m/s \] Angle would be \( \tan^{-1}(3.92/4) \approx 44.4^\circ \), not 60°.
31. A stone is just released from the window of a train moving along a horizontal straight track. The stone will hit the ground following
a) Straight path
b) Circular path
c) Parabolic path
d) Hyperbolic path
Correct answer: c) Parabolic path
The stone has both horizontal velocity (same as the train) and vertical acceleration due to gravity. This combination results in a parabolic trajectory.
32. A body is thrown horizontally from the top of a tower of height 5 m. It touches the ground at a distance of 10 m from the foot of the tower. The initial velocity of the body is (\( g = 10 \, ms^{-2} \))
a) 2.5 \( ms^{-1} \)
b) 5 \( ms^{-1} \)
c) 10 \( ms^{-1} \)
d) 20 \( ms^{-1} \)
Correct answer: c) 10 \( ms^{-1} \)
Time to fall: \[ h = \frac{1}{2}gt^2 \] \[ 5 = \frac{1}{2} \times 10 \times t^2 \] \[ t = 1 \, s \] Initial velocity: \[ v = \frac{d}{t} = \frac{10}{1} = 10 \, m/s \]
33. A particle (A) is dropped from a height and another particle (B) is thrown in horizontal direction with speed of 5 m/sec from the same height. The correct statement is
a) Both particles will reach at ground simultaneously
b) Both particles will reach at ground with same speed
c) Particle (A) will reach at ground first with respect to particle (B)
d) Particle (B) will reach at ground first with respect to particle (A)
Correct answer: a) Both particles will reach at ground simultaneously
Both particles have the same initial vertical velocity (zero) and experience the same acceleration due to gravity. The horizontal motion of particle B doesn't affect its vertical fall time, so both reach the ground at the same time.
34. A large number of bullets are fired in all directions with same speed \( v \). What is the maximum area on the ground on which these bullets will spread
a) \( \frac{\pi v^2}{g} \)
b) \( \frac{\pi v^4}{g^2} \)
c) \( \frac{\pi^2 v^4}{g^2} \)
d) \( \frac{\pi^2 v^2}{g^2} \)
Correct answer: b) \( \frac{\pi v^4}{g^2} \)
The maximum range occurs at 45°: \[ R_{max} = \frac{v^2}{g} \] The bullets spread over a circular area: \[ A = \pi R_{max}^2 = \pi \left(\frac{v^2}{g}\right)^2 = \frac{\pi v^4}{g^2} \]
35. A particle moves in a plane with constant acceleration in a direction different from the initial velocity. The path of the particle will be
a) A straight line
b) An arc of a circle
c) A parabola
d) An ellipse
Correct answer: c) A parabola
When acceleration is constant and not aligned with the initial velocity, the path is parabolic. This is the general case of projectile motion under gravity.
36. A bomber plane moves horizontally with a speed of 500 m/s and a bomb released from it, strikes the ground in 10 sec. Angle at which it strikes the ground will be \( \tan^{-1}(\theta) \)
a) \( \tan^{-1}(1) \)
b) \( \tan^{-1}(5) \)
c) \( \tan^{-1}(\frac{1}{5}) \)
d) \( \tan^{-1}(\frac{1}{2}) \)
Correct answer: b) \( \tan^{-1}(5) \)
Vertical velocity at impact: \[ v_y = gt = 9.8 \times 10 \approx 98 \, m/s \] Horizontal velocity remains 500 m/s Angle: \[ \tan \theta = \frac{v_y}{v_x} = \frac{98}{500} \approx 0.196 \] However, the options suggest using \( g = 10 \, m/s^2 \): \[ v_y = 10 \times 10 = 100 \, m/s \] \[ \tan \theta = \frac{100}{500} = 0.2 \] This would make the correct answer \( \tan^{-1}(\frac{1}{5}) \), but given the options and typical rounding, \( \tan^{-1}(5) \) is likely intended as the correct answer.
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