The beauty of physics lies in its ability to explain the motion of objects, not just in a straight line, but also in a plane. This introduces the intricacies of two-dimensional motion, combining both vertical and horizontal components. Concepts like projectile motion, relative velocity, and angular motion all come into play. To enhance your grasp on this topic, we have prepared 15 multiple-choice questions:
1. An object is projected horizontally from a height. What path will it follow?
Answer:
Explanation:
An object projected horizontally under the influence of gravity follows a parabolic path.
2. In a projectile motion, which component of velocity remains unchanged?
Answer:
Explanation:
In the absence of air resistance, the horizontal component of velocity in projectile motion remains constant.
3. Two vectors are said to be equal if:
Answer:
Explanation:
Two vectors are equal only if they have the same magnitude and direction.
4. The angle between the resultant vector and a component vector is always:
Answer:
Explanation:
The resultant vector is always perpendicular to the component which is not acting in the direction of the resultant.
5. What is the time of flight for a projectile launched horizontally?
Answer:
Explanation:
The time of flight for a horizontally launched projectile only depends on the height and gravitational acceleration.
6. Which of the following is not a vector quantity?
Answer:
Explanation:
Speed has only magnitude and no specific direction, so it’s a scalar.
7. If two vectors are represented in magnitude and direction by the two adjacent sides of a rectangle taken in the same order, then their resultant is represented in magnitude and direction by:
Answer:
Explanation:
This is the rule of the parallelogram law of vectors.
8. The relative velocity of A with respect to B is given by:
Answer:
Explanation:
Relative velocity is found by subtracting the velocity vectors.
9. The maximum height reached by a projectile is independent of:
Answer:
Explanation:
The horizontal range doesn’t influence the maximum height attained by the projectile.
10. The angle at which the range and height of a projectile are the same is:
Answer:
Explanation:
At 45°, the range and maximum height of a projectile become equal for a given initial velocity.
11. If an object is moving in a circular path at a constant speed, its:
Answer:
Explanation:
Even if the speed is constant, the direction of velocity changes continuously in circular motion, making the velocity vector change as well.
12. What is the magnitude of the resultant of two equal vectors at an angle of 60° to each other?
Answer:
Explanation:
The resultant R of two vectors A and B with an angle θ between them is given by R² = A² + B² + 2ABcos(θ). If A = B and θ = 60°, the resultant becomes 1.5 times the magnitude of one vector.
13. An airplane is flying north at 200 km/h and there is a wind blowing east at 50 km/h. What is the resultant velocity of the airplane with respect to the ground?
Answer:
Explanation:
The resultant velocity will be the vector sum of the airplane’s velocity and the wind velocity. This can be solved using the Pythagoras theorem and will give a resultant of 206 km/h in a northeastern direction.
14. For a projectile launched from the ground, the time taken to reach its maximum height is:
Answer:
Explanation:
For a projectile, the time taken to ascend to the maximum height is equal to the time taken to descend from that height, making it half the total time of flight.
15. When is the angular velocity and linear velocity of a rotating object the same?
Answer:
Explanation:
The relation between angular velocity (ω) and linear velocity (v) is given by v = ωr. They will be the same when the radius (r) is one.