Physics Subjective Test

Questions and Answers

What is the work done by gravity when a mass of 50 kg is lifted to a height of 10 meters?

3000 J

4900 J (correct)

5000 J

9800 J

How far should the second child sit from the pivot to balance the seesaw?

1.5 meters

5 meters

3 meters

2.25 meters (correct)

What is the torque produced by a force of 600 N applied at a distance of 5 meters from the pivot?

3000 N-m (correct)

600 N-m

1800 N-m

1500 N-m

What is the formula used to calculate power in relation to work and time?

P = W / t Signup and view all the answers

What is the gravitational force acting on a mass of 3 kg?

29.4 N Signup and view all the answers

What is the formula used to calculate work done?

W = F × d Signup and view all the answers

If the force F is 200 N and the velocity v is 20 m/s, what is the power P calculated in watts?

4000 W Signup and view all the answers

What does the equation W × x = 0 indicate about the weight of the rod?

The rod's weight is balanced at the pivot Signup and view all the answers

Considering the balance moment equation, what can be inferred if 1.5 + W × x = 1.5?

The system is in static equilibrium Signup and view all the answers

What physical interpretation can be derived from the statement that the weight of the rod W = 0 with regard to balancing?

The rod's weight does not influence the balancing of moments Signup and view all the answers

What is the distance from the pivot to the second child when the system is in equilibrium?

2.25 meters Signup and view all the answers

When considering uniform bodies, where is the center of gravity located?

At the geometric center Signup and view all the answers

What principle is used to find the center of gravity for non-uniform bodies?

The balancing method or plumb line method Signup and view all the answers

In translational equilibrium, what condition must be satisfied?

The vector sum of all forces must be zero Signup and view all the answers

Which condition defines rotational equilibrium?

The sum of all moments about any axis must be zero Signup and view all the answers

What would happen if the moments were not equal about a pivot in a system with two children of different masses?

The system will rotate about the pivot Signup and view all the answers

If a uniform rod is balanced at its midpoint, what does this indicate about its center of gravity?

It is located at the midpoint of the rod Signup and view all the answers

What is the calculated power output if the force exerted is 4000 N over a distance covered in 1 second?

4000 watts Signup and view all the answers

What is the maximum number of marks available for Section A in this test?

10 Marks Signup and view all the answers

What force is applied to the 10-meter-long plank in the example?

600 N Signup and view all the answers

Which of the following describes a condition for a rigid body to be in equilibrium?

The net force acting on the body should be zero. Signup and view all the answers

How far from the pivot is the mass of 2 kg placed on the seesaw?

0.75 meters Signup and view all the answers

What is the formula for calculating work done against gravity when raising a mass?

Work = mass × gravitational force × height Signup and view all the answers

When a 50 kg mass is raised by 10 meters, what is the calculated work done against gravity? (Use g = 9.8 m/s²)

1960 J Signup and view all the answers

What is the formula for power in terms of force and velocity?

Power = force × velocity Signup and view all the answers

What is the constant speed of a car moving under a force of 200 N as mentioned in the question on power?

20 m/s Signup and view all the answers

Study Notes

Exam Structure

The paper comprises 7 compulsory questions divided into two sections: Section A (Short Answer) and Section B (Long Answer).
Section A consists of 4 questions with a maximum score of 10 marks.
Section B contains 5 to 7 questions worth a maximum of 10 marks.

Key Concepts in Equilibrium

Conditions for Equilibrium:
- Translational Equilibrium: The sum of all forces acting on the body must equal zero (ΣF = 0).
- Rotational Equilibrium: The sum of all moments (torques) acting on the body about any axis must equal zero (Στ = 0).

Working with Moments

A seesaw is balanced using the principle of moments, which involves calculating distances from the pivot to ensure equal torque on both sides.
Example problem involves balancing a seesaw with two children of different masses at varying distances from the pivot.

Work and Energy

Work Done against Gravity Formula: W = m × g × h
- m = mass (kg), g = acceleration due to gravity (9.8 m/s²), h = height (m).
Example calculation for raising a 50 kg mass by 10 meters yields 4900 joules of work done against gravity.

Torque Calculation

Torque (τ) is calculated as τ = F × d, where:
- F = force applied,
- d = perpendicular distance from pivot.
Example problem calculates torque due to a 600 N force at an angle of 30° applied at the end of a 10-meter plank.

Centers of Gravity

Uniform Bodies: The center of gravity (CG) is located at the geometric center (e.g., midpoint for a uniform rod, center for a sphere).
Non-Uniform Bodies: The CG can be found using the principle of moments or balancing techniques.

Power Calculation

Power Formula: P = Work / Time, can be expressed in terms of force and velocity as P = F × v.
Example demonstrates a car moving at 20 m/s under 200 N of force results in a power output of 4000 watts.

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Description

Prepare for your Physics Board Exam with this subjective test designed for the Victory 2025 syllabus. This quiz covers essential concepts related to the conditions for equilibrium and other fundamental principles in physics. Test your understanding and readiness for upcoming assessments.

Physics Subjective Test - 2024