# Physics

## Physics Questions and Answers

Physics

The formula for pressure is P = F/A In this equation, P stands for pressure while F stands for force and A stands for area. Pressure is typically measured in a unit called the Pascal. So what this...

Latest answer posted December 24, 2009, 2:12 pm (UTC)

Physics

Impulse is the change in momentum of an object. There are two impulses that your egg design will have to deal with. The first impulse is from the drop itself. Its momentum will increase due to the...

Latest answer posted April 21, 2013, 5:52 pm (UTC)

Physics

We have the position vector given in terms of time t. r(t) = t^3*i + t^2*j To find the velocity vector we have to differentiate r(t) with respect to time. r'(t) = 3t^2*i + 2t*j The vector...

Latest answer posted March 22, 2011, 3:25 am (UTC)

Physics

They both hit the ground at the same time. So your answer is C. Gravity works on the bullets just the same regardless of velocity. The bullets have to be the same calibre and weight for this to...

Latest answer posted June 1, 2009, 8:55 am (UTC)

Physics

In order to find the answer to this question, you need to know the following equation: m = dv Where m is mass, d is density, and v is volume. In this case, you are looking for mass, you have...

Latest answer posted December 20, 2009, 1:19 am (UTC)

Physics

The displacement of water is an excellent way to measure the volume of a solid provided that the solid does not dissolve in water and that it does not float. If the object floats then it will not...

Latest answer posted September 22, 2012, 3:55 am (UTC)

Physics

For a potential difference V across a resistor R, the current I that flows through the resistor is given by Ohm's law as I = V/R As current is inversely proportional to resistance, for the same...

Latest answer posted February 29, 2012, 1:47 am (UTC)

Physics

Let the volume of the block be V and the density D. The mass of the block is D*V. In an oil-water interface with oil having a density of 800 kg/m^3 floating on water with a density of 1000 kg/m^3,...

Latest answer posted April 3, 2012, 1:18 am (UTC)

Physics

Rearranging terms, E ( 4(3.1416)d^2 ) = P, so E ( 4(3.1416)[.9m^2] ) = 1200 lm E ( 12.57 [.81m^2] ) = 1200 lm E (10.17m^2) = 1200 lm E = 1200 lm / 10.17 m^2 E = 118 lm/m^2

Latest answer posted June 11, 2011, 1:30 am (UTC)

Physics

A hockey stick is used as a lever. When you hold a hockey stick, the hand with which you hold the stick at the top end serves as the fulcrum. The other hand with which you catch the stick in the...

Latest answer posted November 10, 2011, 3:04 pm (UTC)

Physics

Mass is "the amount of stuff" in an object. That is, the amount of atoms and molecules present. Mass in science, is measured in the metric system using units such as kilogram (about 2.2...

Latest answer posted November 12, 2011, 1:22 pm (UTC)

Physics

When the basketball is thrown up an initial velocity is imparted to it. This gives the ball a kinetic energy equal to (1/2)*m*v^2 where m is the mass of the ball and v is the velocity with which it...

Latest answer posted December 2, 2012, 9:34 am (UTC)

Physics

The meaning of the original statement is that if you have a cubic meter of water (an amount of water that is one meter in height, one meter in width, and one meter in depth), that amount of water...

Latest answer posted December 15, 2009, 12:02 am (UTC)

Physics

Yes, an object can have both of these at the same time. Potential energy is energy that is stored in an object. Kinetic energy is the energy that is associated with motion. So what you have to...

Latest answer posted November 23, 2009, 11:53 am (UTC)

Physics

The density of the table tennis ball is 0.084 g/cm^3. This has to be converted in terms of SI units. It is equal to 0.084*10^-3/(0.01)^3 kg/m^3 = 84 kg/m^3. The density of water is 1 g/cm^3 which...

Latest answer posted October 8, 2011, 1:45 am (UTC)

Physics

The safe answer is C. See below why it could also be D: The best way to think of weight is this: weight is the measurement of resistance of a given mass to falling. On the earth, everything that...

Latest answer posted December 12, 2009, 12:10 pm (UTC)

Physics

The Young's modulus is a constant for metals in the range of values of stress for which Hooke's law is valid. It can be determined by the relation: Young's modulus= Tensile Stress/ Tensile Strain....

Latest answer posted November 18, 2010, 7:39 pm (UTC)

Physics

The law of conservation of energy states that the total energy in an isolated system does not change. It may change form, for example mechanical energy may get converted to thermal energy,...

Latest answer posted November 19, 2011, 12:10 pm (UTC)

Physics

The term "relative density" means the same as "specific gravity." It is a measure of how dense one thing is when compared to a given reference. The reference is usually water. With respect to...

Latest answer posted December 15, 2009, 11:13 am (UTC)

Physics

This is because of the amount of force that is put on your foot and the area over which the force is applied. Since pressure = force/area, the same force on a smaller area means more pressure....

Latest answer posted December 22, 2009, 12:24 pm (UTC)

Physics

When a ball is thrown vertically upwards, there is an acceleration acting on it due to the gravitational force of attraction of the Earth equal to 9.8 m/s^2. This acts in a direction vertically...

Latest answer posted February 26, 2012, 9:34 pm (UTC)

Physics

If I understand this question correctly, the angle of reflection should be 30 degrees with respect to the mirror as well. The angle of the incoming ray and the angle of the ray that is reflected...

Latest answer posted March 31, 2010, 10:55 pm (UTC)

Physics

When two resistors with resistance R1 and R2 are connected in parallel, the equivalent resistance of the configiration is given by 1/R = (1/R1 + 1/R2). And for two resistors R1 and R2 connected in...

Latest answer posted January 3, 2012, 2:53 pm (UTC)

Physics

At sea level, the approximate value of atmospheric pressure in those units of measure is as follows: 101.3 kPa which is how it is usually expressed. In pascals, it is 101325 pascals. The first of...

Latest answer posted December 25, 2009, 11:08 am (UTC)

Physics

The energy of a quantum of light or a photon is given by the formula E = h*nu = h*c/lambda, where nu is the frequency of the light, lambda is the wavelength, c is the speed of light and h is the...

Latest answer posted March 12, 2011, 11:20 am (UTC)

Physics

The ball is stationary in the students hand when it is dropped. Once the student drops the ball, it is acted upon by the gravitational force of the Earth. This force creates an acceleration of 9.8...

Latest answer posted November 29, 2010, 8:52 pm (UTC)

Physics

Forces are considered balanced when all of the combined forces lead to no change in the motion of the object. For example, when a book is sitting on a table, the force of gravity is pushing...

Latest answer posted November 14, 2008, 4:45 am (UTC)

Physics

The electrical conductivity of a metal has the SI units Siemens/meter. This is a reciprocal of the resistivity that is expressed in terms of ohm*m. Electrical conductivity of a metal is not the...

Latest answer posted November 4, 2011, 1:41 pm (UTC)

Physics

A man in a metallic cage is not affected even when the cage is highly charged due to what is known as the Faraday cage effect. In a state of equilibrium, charges are as far from each other as...

Latest answer posted September 8, 2011, 1:16 am (UTC)

Physics

At a height h, the gravitational potential energy P of an object with mass m is given by the relation P = m*g*h. If the object is considered to be a closed system, it is assumed that there is no...

Latest answer posted November 21, 2011, 9:27 am (UTC)

Physics

According to Ampere's law, the force between two wires carrying a current I1 and I2 and which are separated by a distance r is given as F= 2*K*I1*I2 / r, where K is a constant. In the problem, when...

Latest answer posted December 28, 2010, 6:23 pm (UTC)

Physics

Most of the time, people ask this question with the idea of a Newtonian "feather vs. bowling ball" concept in mind. Based on those terms, the typical answer is correct: two objects will fall at the...

Latest answer posted July 11, 2014, 4:34 am (UTC)

Physics

A 145 g baseball is thrown with a speed of 25 m/s. When the thrower picks up the ball it is at rest. When it leaves the hand of the person that is throwing the ball it has a speed of 25 m/s. An...

Latest answer posted March 26, 2012, 11:26 am (UTC)

Physics

The pressure would be doubled if the same force acted on half the area. The pressure in the first scenario is 50 N/m^2 while the pressure in the second scenario is 100 N/m^2 The way you get this is...

Latest answer posted February 1, 2010, 1:26 pm (UTC)

Physics

The 66 kg skier slides down a hill 25 m high. The potential energy of the skier at the top of the hill that has a height of 25 m is given by PE = m*g*h = 66*9.8*25. At the bottom of the hill all...

Latest answer posted April 3, 2012, 11:16 am (UTC)

Physics

The simple harmonic motion is by definition the motion of a point which is subjected to a force that is proportional to the deviation of the point from the equilibrium position. For mass spring...

Latest answer posted October 18, 2013, 11:36 am (UTC)

Physics

The applied force moves an object from A( 1 , 3) to B( 3 , 7). The slope of the line joining these points is (7 - 3)/( 3 - 1) = 4 / 2 = 2. The slope of the direction vector is 3/2. The angle...

Latest answer posted February 20, 2011, 11:57 am (UTC)

Physics

When a spring is extended or compressed from its equilibrium length, the change in length is related to the force applied by the relation F = -kx, where F is the force applied, k is the spring...

Latest answer posted February 23, 2011, 10:06 pm (UTC)

Physics

Remember we have the expressions: E = A * (dB)/(dt) A = pi r^2 E = pi r^2 (dB)/(dt) where: A = area of the coil r = radius = diameter/2= 10.2/2 = 5.1 cm = 0.051 m db = change in magnetic...

Latest answer posted April 15, 2013, 5:35 am (UTC)

Physics

The height of mercury above the bowl in a barometer is a measure of the pressure of air pushing on the mercury in the bowl. The mass of the mercury above the bowl times the force of gravity is...

Latest answer posted December 28, 2009, 9:39 pm (UTC)

Physics

eNotes policy only allows for one question per submission so I have editted your question accordingly. I have decided to demonstrate the more difficult question so if you understand these concepts,...

Latest answer posted March 25, 2013, 10:54 pm (UTC)

Physics

When a water balloon is thrown towards a person it bursts when an attempt is made to catch it because the material that the balloon is made of cannot withstand a large force. The water filled in...

Latest answer posted November 5, 2011, 12:57 am (UTC)

Physics

The correct answer here is C -- it increases by a factor of 9. Here's why: The formula for kinetic energy is k = .5 mv^2 or k = .5*m*v*v Where k is kinetic energy, m is the mass and v is the...

Latest answer posted November 19, 2009, 11:25 pm (UTC)

Physics

The kinetic energy of an object with mass m and which has a speed of v is given by (1/2)*m*v^2. The change in the kinetic energy of the object as the speed changes is proportional to the square of...

Latest answer posted March 26, 2012, 1:29 pm (UTC)

Physics

One major problem with intrasolar and interstellar communication is the vast distances involved. On Earth, radio communication is all-but instantaneous, because radio waves travel at the speed of...

Latest answer posted October 29, 2012, 9:47 pm (UTC)

Physics

The correct answer here is B -- the weight of the rocket decreases. The point of this question appears to be the difference between weight and mass. Mass is a measure of the amount that is in an...

Latest answer posted December 11, 2009, 11:48 pm (UTC)

Physics

Thte way you have worded this, the ball is below the ceiling, so the potential energy with respect to the ceiling is negative. PE = mgh, and since the zero position is the ceiling, the potential...

Latest answer posted November 22, 2009, 10:15 am (UTC)

Physics

The wording of this question is a bit confusing. It appears that the question is asking for an explanation of how force and mass are related to each other. That's a part of Newton's second law. The...

Latest answer posted November 10, 2019, 8:06 pm (UTC)

Physics

The answer is D. This can be easily determined by using the formula for linear expansion due to temperature (or linear thermal expansion). This formula is stated as change in length = alpha times...

Latest answer posted December 10, 2009, 10:51 pm (UTC)