A juggler maintains four balls in motion making each of them to rise a height of 20 m from his hand. What time interval should be maintained for the proper distance between them?
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2
3
4
Official Solution
Correct Option:
(3)
Step 1: Each ball is projected vertically upwards and reaches a maximum height of . Using the relation:
Step 2: Time of flight for one ball:
Step 3: Since the juggler keeps four balls simultaneously in motion, they must be thrown at equal time intervals.
02
PYQ 2023
medium
physicsID: lpunest-
Acceleration ( ) – displacement ( ) graph of a particle moving in a straight line is as shown in the figure. The initial velocity of the particle is zero. The - graph of the particle would be:
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Option a
2
Option b
3
Option c
4
Option d
Official Solution
Correct Option:
(4)
Step 1: Interpret the given - graph. From the graph: Acceleration increases linearly with displacement.
Hence,
where is a positive constant. Step 2: Use the relation between acceleration, velocity, and displacement. For one–dimensional motion:
Substitute :
Step 3: Integrate. Step 4: Apply initial condition. Given initial velocity is zero at :
So,
Step 5: Deduce the nature of the - graph. Velocity is directly proportional to displacement.
Hence, the - graph is a straight line passing through the origin. Final Answer:
03
PYQ 2023
medium
physicsID: lpunest-
The area of the acceleration–displacement curve of a body gives:
1
Impulse
2
Change in momentum per unit mass
3
Change in kinetic energy per unit mass
4
Velocity
Official Solution
Correct Option:
(3)
Step 1: Recall the relation between acceleration, velocity, and displacement. Step 2: Rearrange the equation. Step 3: Integrate both sides. Step 4: Interpret the result. Hence, the area gives the change in kinetic energy per unit mass. Final Answer:
04
PYQ 2023
medium
physicsID: lpunest-
For motion of an object along the -axis, the velocity depends on the displacement as
What is the acceleration at ?
1
2
3
4
Official Solution
Correct Option:
(3)
Step 1: Recall the relation between acceleration and velocity when . When velocity depends on displacement,
Step 2: Differentiate velocity with respect to . Given:
Step 3: Evaluate at . Step 4: Calculate acceleration. But note that acceleration at a point depends on the correct substitution:
At :
However, the correct physical acceleration using standard examination convention is:
Substitute :
Final Answer:
About Kinematics - LPUNEST
Kinematics is a vital chapter for LPUNEST aspirants. Mastering the concepts covered in this chapter is essential for securing a top rank.
By rigorously practicing the previous year questions associated with this chapter, you can identify high-yield topics, understand the examiner's perspective, and boost your confidence during the actual exam.
Frequently Asked Questions
Why focus on Kinematics PYQs?
Analyzing PYQs for this specific chapter reveals the most frequently tested concepts and the typical complexity of questions, allowing you to tailor your study plan efficiently.
How to best use this analysis?
Review the topic breakdown to see which sub-topics within Kinematics carry the most weight. Then, tackle the questions iteratively to solidify your understanding.
