Mechanics

Work done = force x distance moved in direction of line of force

Assuming that the ball falls straight down (i.e. in the direction in which gravity acts):

W = F d

where F = weight of ball in newtons = mass x gravitational field strength

= m g

where g is about 9.8 N/kg on Earth

So W = m g d

= 0.8 kg x 9.8 N/kg x 2.5 m

= 19.6 Joules

Kinetic energy = 1/2mv2

momentum = mv.

If you could change the mass at the same time as the velocity to keep the kinetic energy constant, then you could change momentum without changing the kinetic energy.

Suppose you have a mass of 4kg moving at 1m/s ... it has a momentum of 4 units (N-s) and a Kinetic Energy of 2 units (Joules).

The mass could be burned to make the craft go faster .. say that it increased its speed to 2m/s but in the process the mass decreased to 1kg .. the Kinetic energy would still be 2 Joules, but the momentum would now be 2 units. (not a very efficient engine, this).

Another burn of the mass, and now it only weighs 0.5kg .. however the speed has increased to 2*(sqrt(2)) m/s, KE is still 2J, and momentum is now .. Sqrt(2) N-m ..

Provided your destruction of mass occurred at the correct rate as the velocity changes, yes you can change momentum without changing kinetic energy. Just not arbitrarily.

inertia

How do you determine the net force on an object?

Decide which direction is positive motion.

Motion is the opposite direction is negative

The forces must in a straight line!!

Add all the forces in straight line acting on the object.

Example

To the right is positive

A 5 N force pushes a 10 Kg object to the right.

A 2 N force pushes the same 10 Kg object to the left.

The 5 N forces is positive and the 2N force is negative

Net force = +5 N - 2 N = + 3 N

To determine the acceleration use Newton's 2nd law of motion

F = Mass * acceleration

+ 3 N = 10 Kg * a

a = 10 Kg ÷ + 3 N

a = +3 ⅓ m/s^2

The positive sign means the object is accelerating to the right!!

If the forces are not linear, you must use vectors, but the net force in any direction is still the sum of the vectors in that direction.

In SI, torque is measured in newton metres (N.m). The percentage torque varies according to the design and specifications of a motor.

Torque is not measured as a percentage.

Recall that a roller coaster is a gravity operated, fixed course, recreational vehicle. And also note that velocity is like speed, only with a direction vector associated with it. Velocity is associated with a roller coaster pretty much all along its route; it's always being acted on by gravity. The cars are acted on by another force, which is basically a "push" or "pull" with a direction vector, to increase their velocity a bit. The cars are hauled to the top of a grade, and then pushed over the top to begin their gravity-assisted acceleration. The velocity rises rapidly, and then other forces act on the cars (and the riders) as the vehicle acts on the rails and has the rails act back on them. Lots of things going on at once. Any time the cars of the ride change direction, they change velocity. They may or may not change speed, but a direction change alone is a velocity change. It's that simple. The cars are given potential energy by being lifted up the ramp. Then that potential energy is converted into kinetic energy, into motion, by gravity. (Note that some rides "throw" the car along a track to give it kinetic energy, and it coasts for the rest of the ride and is acted on by gravity and the rails. The bottom line is that any speed change or direction change must be accomplished by a force acting on the cars, and that's how velocity will change. The physics subject of mechanics deals with this pretty well, and it is fairly easy to at least qualify the things that are happening. Following qualification, which is basically stating "what" is happening, we can move on to quantify them to determine "how much" is involved. A link is provided below so you can gather further information.

There are no mirrors in a periscope - they use prisms. But you could use two at 45 degrees to the object and observer, parallel to one another

The forces add together.

Debit Stationary account

Credit XYZ account

Should be closest to the passenger side front wheel

200 kilometers per hour is 124.3 mph

This is an indication that the air pressure is decreasing.

velocity of a wave equals wave frequency times wave length.

A spinning top is a moving mass, and this represents a form of mechanical energy we call kinetic energy, which is the energy of motion.

Because it's harder to get something to start moving than keep it moving if it already is. Coefficients of friction are merely constants dependent on the two surfaces in contact. Carpet has a higher coefficient of friction than ice because carpet has more microscopic bumps which oppose motion than smooth ice does.

A class three lever is where the load is one side of the force and the fulcrum is on the other side of the force. An example is a pair of tweezers. Another example is the secondary lever in a pair of fingernail clips, i.e. the part that closes on the fingernail. (The first lever in a pair of fingernail clips, i.e. the part that you press on, is an example of a second class lever.)

Just reacting to this might lead someone to say yes to the question. But no, liquids with a higher density don't always have a higher viscosity. Different liquids have mechanical properties based on their composition and other variables. Temperature is one. A temperature change of 5 degrees can double the viscosity of some things, and yet others will maintain a fairly constant viscosity over a broad temperature range. There can be a lot of range in material properties. The general rule (though not a hard and fast one) is that the larger the molecules of a substance, the greater its viscosity. Compare black strap molasses to the amazing metal mercury. At room temperatue, the molasses takes quite a while to come out of the bottle. Mercury will come out of a bottle about as fast as water would. The mercury has a dynamic viscosity of about 1.5 cP, while that of water is a tiny bit over 1 cP. Olive oil rates about 85 cP, and molasses goes up way beyond that. Let's take a little trip through time and space. Remember those things that played vinyl records? Turntables? They'd gone "out of style" a while back - 'til the DJ's brought 'em back! Anyway, remember the tiny needle that tracked the groove in the record? That's the stylus. And the cartridge (or "cart") is the thing that the stylus fit into. The cart was put onto the head shell, and the headshell onto the end of what was called the tonearm. And the tonearm had a little lever that lifted the whole arm up. Are we good? Now let's look at the action of the arm. If we put a record on the turntable, unlocked the tonearm, and then lifted it with the lift lever (or cueing lever), we'd then move the tonearm over to the place (the track) where we wanted to put the stylus. This is how we cue the tonearm. We'd cue the tonearm, and them push the lever down to drop the arm. But the arm wouldn't drop. I wasn't supposed to. The arm would actually "coast" or "glide" down in slow motion. If you have a chance to see this in action, watch it. The reason for the "slow motion" descent was that there was some silicone tonearm damping fluid in the little cylinder that had to collapse for the tone arm to go down. And if you had a little bottle of this silicone tone arm damping fluid, you could invert it, go warm your coffee in the microwave oven and return to find it hadn't moved very much at all. It would be hard to detect its motion. Its viscosity is very, very high. And it's about as dense as vegetable oil. Who knew, huh? And let's not even get started about glass.

You must stick the label on the weight while it's at rest, and only then draw it

to one side and release it to begin the to-and-fro motion of the pendulum.

Scales and kitchen use.

It will eventually straighten out as it escapes gravity.

The bolt could have been faulty, or the torque wrench may not be calibrated.

The fulcrum on a can opener is where the hook meets the lip of the can. The can opener is a class 1 lever.