High School Physics Lab

Q&A: Finding Volume of a Floating Object

2008-02-13T14:56:00.017Z

The following question was asked in the comments section of the article Archimedes' Principle Explained.Q: Can you just explain how to measure the volume of an irregularly shaped object which floats in water? Can we use Archimedes' principle? How?A: It is certainly possible to do so using Archimedes' principle, provided the density of the object is known. The key here is to find the mass of the

Problem: Materials #4

2007-12-01T15:30:00.000Z

A cube of ice is floating in a salt solution of density 1.25 times the density of pure water in a beaker. When the ice melts, the level of the solution in the vesselA. risesB. fallsC. remains unchangedD. falls at first and then rises to the same height as beforeSolutionShow solution >>The answer is A.A non-mathematical explanation would be that since the ice is floating, its mass would be the

Problem: Materials #3

2007-10-21T06:31:00.000+01:00

Within a certain type of star called a neutron star, the material at the centre has a mass density of 1.0 × 1018 kg m-3. If a small sphere of this material of radius 1.0 × 10-5 m were somehow transported to the surface of the earth, what would be the weight of this sphere? (Assume that g = 10 m s-2)A. 1000 NB. 4200 NC. 4.2 × 104 ND. 7.0 × 104 NE. 3.1 × 109 NSolutionShow solution >>The answer

Problem: Kinematics #4

2007-09-29T18:11:00.000+01:00

A train covers half the distance of its journey with a speed 20 m s-1 and the other half with a speed of 40 m s-1. The average speed of the train during the whole journey isA. 25 m s-1B. 27 m s-1C. 30 m s-1D. 32 m s-1E. 35 m s-1SolutionShow solution >>The answer is B.Let the total distance travelled by the train be d and the time taken for it to complete the first half and second half of the

The Concept of… Force

2007-08-11T11:22:00.000+01:00

Force is one of the most fundamental concepts of physics. The concept of force has formed part of statics and dynamics since ancient times. The modern concept of force is commonly explained in terms of Newton's three laws of motion set forth in his Principia Mathematica (1687).What is force?Force can be described as a push or pull. A force upon an object is always a result of interaction with

Problem: Heat #1

2007-07-15T06:33:00.000+01:00

The air in a room consists principally of nitrogen and oxygen. The molecular weight of nitrogen (N2) is 28 g/mole and the molecular weight of oxygen (O2) is 32 g/mole. The air is in thermal equilibrium. Which statement is true?A.The average speeds of the nitrogen and oxygen molecules are equal.B.The average kinetic energies of the nitrogen and oxygen molecules are equal.C.The oxygen molecules

Problem: Dynamics #1

2007-06-30T12:24:00.000+01:00

A stone thrown vertically upwards from the Earth’s surface travels until a height of h and falls back to its original position. If air resistance can be ignored, which graph below best represents the change of force, F which acts on the stone with its distance travelled, s?A.C.B.D.SolutionShow solution >> The answer is D. Because the stone is thrown upwards, the gravitational field strength of

Problem: Measurements #1

2007-06-02T16:58:00.001+01:00

x1, y1 and x2, y2 are two sets of values that are related according to the following equation:The points (x1, y1) and (x2, y2) lie on the graphA. C. B. D. SolutionShow solution >>The answer is C.The above equation can be rearranged in this way:When xy = k, that means y is inversely proportional to x. The graph y versus x will be like the one in C. Hide solution <

The Relationship between Variables (Part II)

2007-05-29T17:27:00.001+01:00

This article is a continuation from Part I, which discusses about direct proportion. Inverse ProportionTwo sets of readings for the quantities x and y are given in the table below.x34612y4321Here, when x is doubled, y is halved; when x is trebled, y is one-third its previous value and so on.We say that y is inversely proportional to x, or y varies inversely as x, that is The graph of y versus x

Problem: Kinematics #3

2007-05-28T05:57:00.000+01:00

The figure above shows a displacement versus time squared (t2) graph for the motion of an object.Which of the following motion can be represented by this graph?A. A ball that is travelling at terminal velocity.B. A ball that is falling freely from a stationary position.C. A ball that bounces back from the floor.D. A ball that is travelling on a rough surface.SolutionShow solution >> The answer is

The Relationship between Variables (Part I)

2007-05-26T06:09:00.002+01:00

One of the most important mathematical operations in physics is finding the relationship between variables. Through the study of these relationships, we can know how a change in one variable affects another variable, thus enabling us to make predictions and conclusions easily.For example, an automobile maker will want to know how the mass of a car affects its acceleration, so that they can design

Problem: Kinematics #2

2007-05-25T05:46:00.000+01:00

The figure above shows two objects, P and Q moving with velocities 30 m s-1 and 20 m s-1 respectively towards each other on a straight line.How long, after that instant, will P and Q meet?A. 100.0 sB. 83.3 sC. 20.0 sD. 13.3 sSolutionShow solution >> The answer is C.Let the distance travelled by P and Q before they meet each other be d1 and d2 respectively. Here, we can form an equation:d1 + d2=

Problem: Materials #2

2007-05-11T12:27:00.000+01:00

The density of an object is ¾ of the density of water. If the object is floating on the water surface, then the ratio between the volume of object above the water surface and the volume of object below the water surface isA. 1:4B. 1:3C. 3:4D. 4:3SolutionShow solution >> The answer is B.This is a problem that requires the application of Archimedes’ principle.We know that the density of the object

Problem: Materials #1

2007-05-05T06:34:00.001+01:00

An object has a weight of 4 N in air, 3 N in water and 2.8 N in a salt solution. If the density of water is 1000 kg m-3, the density of the salt solution isA. 830 kg m-3B. 1070 kg m-3C. 1200 kg m-3D. 1430 kg m-3SolutionShow solution >> The answer is C.This is a problem that requires the application of Archimedes’ principle. The object has a weight of 4 N in air. Because the upthrust on the object

Archimedes' Principle Explained

2007-04-30T16:50:00.000+01:00

Archimedes' principle is a law that explains buoyancy or upthrust. It states thatWhen a body is completely or partially immersed in a fluid it experiences an upthrust, or an apparent loss in weight, which is equal to the weight of fluid displaced.According to a tale, Archimedes discovered this law while taking a bath. After making this discovery, he is said to have leapt out of his bathtub and

Problem: Kinematics #1

2007-04-29T16:04:00.002+01:00

A stone is released from a height of 20 m and allowed to fall in a straight line towards the ground. Ignoring air resistance, calculatea) the time taken for the stone to reach the ground.b) the velocity of the stone just before it touches the ground(Assume that g = 10 m s-2)SolutionShow solution >>The answers for (a) and (b) are 2 seconds and 20 m s-1 respectively.This is a problem utilising the

The Equations for Uniform Acceleration

2007-04-28T06:58:00.002+01:00

There are four equations for uniform acceleration (also known as the kinematic equations) which are used to describe the motion of an object:1.2.3.4.Where:u – initial velocityv – final velocitya – accelerationt – times – displacementYou may be wondering – why there are four equations instead of one? Notice that each equation has one variable missing. For example, the first equation doesn’t have

Problem: Waves #1

2007-04-22T07:01:00.001+01:00

The frequency of oscillation of a simple pendulum is f1. When the length of the pendulum l is increased to 2l, the frequency of oscillation of the simple pendulum is f2. The value of the ratio f1/f2 isSolutionShow solution >> The answer is D.The formula for the periodic time, T of a simple pendulum is given byand we know thatTherefore, the formula for f of a simple pendulum is given byNow we know

Getting Started

2007-04-20T18:13:00.001+01:00

This post is about getting started in physics in general and also benefiting from the future contents of this blog as promised in the Introduction post.For high school students studying physics at school, you can use your textbook for reference should any need arises.For those who have none or intend to self-study, the following sites and online resources should provide you with texts on high

Introduction

2007-04-20T10:59:00.000+01:00

This is another blog brought to you by InfoFries. This blog aims to help high school physics students cope with their physics lessons, guide them through their examinations and perhaps lead them to success in the field of physics in the future. This shall be done by placing great emphasis on the understanding of basic concepts.The articles posted here are meant to supplement existing physics