Mechanics

At 60 mph it would take 3.41 seconds to cross an American football field.

Yes, balancing the forces acting on an object involves ensuring that the sum of all forces is zero, which means there is no net force acting on the object. This equilibrium condition results in the object either remaining at rest or moving at a constant velocity.

A really long time; about six months at 55 miles per hour.

A plane climbs into the jet stream which is flowing at a rate of 80 miles per hour Traveling with the jet stream for 5 hours the plane covers 1150 miles The plane then reduces its altitude and flies 150.

Yes, but an object with net force of zero may still be moving. The net force is zero if the object is not accelerating.

If an object has no net force acting on it, it will either remain at rest or continue moving at a constant velocity in a straight line, following Newton's first law of motion.

The man would have to go at a speed of 222 miles per hour to cover 555 miles in 2 hours and 30 minutes.

The plane was in the air for 4.5 hours (1,350 miles divided by 300 miles per hour).

The plane was in the air for 4.5 hours. This can be calculated by dividing the distance (1350 miles) by the average speed (300 miles per hour).

Force can be defined as the derivative of momentum with respect to time or: dp/dt = d(mv)/dt

Since the mass stays the same, we can take that out:

m * dv/dt (It's worth noting that this is the derivation of the F=ma equation)

Now to answer your question, this depends on the amount of time the object is being pushed by the wall. If the time is equal, then the wall will apply a greater force on the ball if it bounces back because it has to change the ball's momentum by a greater amount to get it to move back towards the thrower.

Slinky! No, seriously. A slinky at the top of the stairs has POTENTIAL energy, a slinky falling down the stairs has KINETIC energy. Things with the potential to release energy have POTENTIAL energy. Things currently releasing that energy have KINETIC energy. Of course, it could also be a block of uranium, and it's got energy no matter what it's doing. Or it could be a chunk of wood sitting there, it's got thermal & light energy stored inside it, which would be released by rapid oxidization (burning).

In fluid dynamics, a common example of using finite difference method is the discretization of the Navier-Stokes equations to solve for fluid flow equations. This entails approximating spatial derivatives with finite differences on a grid, which allows for numerical simulation of the fluid behavior in a computational domain.

Einstein deduced that mass and energy are equivalent, and that E = mc2 where E = energy, m = mass, c = velocity of light. This of course applies to the actual amount of mass destroyed in a reaction, not to the total masses involved. Thus in a nuclear fission reaction in U-235, only a small amount of the total mass of the U-235 nucleus disappears to form energy, most of it appears in the masses of the two fission fragments, the total energy released is 200 Mev per fission which is about 3 x 10-11 Joules. In a chemical reaction energy is released but at a much smaller proportion of the masses involved. Bearing this in mind you can see that the total energy in objects around us is truly awesome! You can work out some figures, use kilograms for mass and meters/sec for c, E will then be in Joules.

Rock changes involve physical or chemical processes that transform rocks into different forms, but they do not destroy or create matter. These changes are part of the rock cycle, where rocks are constantly being formed, broken down, and reformed. The principle of conservation of matter states that matter is neither created nor destroyed in these processes.

Changes in rocks never create or destroy matter. The principle of conservation of matter states that matter cannot be created or destroyed, only transformed from one form to another. So, changes in rocks may involve physical or chemical processes that alter their composition or appearance, but the total amount of matter remains constant.

If the speed of sound depended on frequency, distant music would sound distorted. Higher frequency sounds would travel faster than lower frequency sounds, causing a shift in the relative timing of different frequencies and resulting in a jumbled and unintelligible sound.

Yes, surgical steel is a good conductor of electricity due to its high iron content. This is why surgical steel is often used in medical instruments and implants that may need to conduct electricity in certain applications.

Motor oil heats faster than water, as water has one of the highest specific heat capacities. (It takes more energy to increase the temperature of 1 kg of water by 1 °C than to increase the temperature of 1 kg of oil by 1°C)

It is not so much the temperature of the water but the pressure that the hot water produces. If you will look at almost any car radiator cap you will notice a warning that says something to the effect
'warning contents under pressure. Do not remove when hot.'

No, all objects in the Universe generate a pulling force on all other objects. The Moon, Sun, planets, asteroids, meteors and stars all have a gravitational field. All humans, animals, trees, planes and buildings possess a gravitaional force, relative in size to its mass.

Two cyclists are traveling the same path. The first cyclist stops every 11 minutes to take a drink. The second cyclist stops every 15 minutes to take a drink. If the cyclists continue to stop at the same rate, after how many minutes will the cyclists be stopped at the same rate?