Physics Midterms Review - Simple Machines, Pressure, and Buoyancy

Fill-in-the-blank practice flashcards covering simple and compound machines, mechanical efficiency, fluid pressure, Pascal's Principle, and Archimedes' Principle.

A single simple machine makes mechanical work easier primarily by changing the magnitude, distance, or __________ of an applied force.

direction

A simple machine consisting of a rigid bar that pivots around a fixed support point is called a __________.

lever

A pair of scissors is a classic example of a compound machine because it combines two levers and two __________.

wedges

A compound machine is fundamentally distinguished from a simple machine because it is composed of __________ or more simple machines working together.

two

In a first-class lever, the fulcrum is located between the effort force and the __________.

load

A screw is structurally a modified __________ plane wrapped spirally around a central cylinder.

inclined

A single fixed pulley attached to a ceiling changes the __________ of the effort force needed to lift a heavy object.

direction

In a wheel and axle mechanism, turning a larger outer wheel generates greater rotational force, or __________, on a smaller attached axle.

torque

A standard mechanical bicycle integrates levers, a wheel and axle system, and __________.

screws

Mechanical efficiency of a machine is defined as the ratio of useful work output to total work input, expressed as a __________.

percentage

Real-world machines cannot achieve 100% mechanical efficiency because a fraction of input energy is always converted into non-useful thermal energy due to __________ and air resistance.

friction

The operational efficiency of motor engine gears or moving joints can be improved by applying __________ like oil or grease to smooth contact surfaces.

lubricants

If an electric winch uses $100\,Joules$ of electrical energy input to deliver $80\,Joules$ of useful mechanical work output, its mechanical efficiency is __________.

$$80\%$$

A machine with a high Ideal Mechanical Advantage (IMA) does not necessarily possess 100% real-world efficiency because moving across greater distances accumulates __________ energy losses.

frictional

An inclined plane distributions required work over a longer distance, which reduces the required __________ force.

effort

An axe blade or chisel used to split a wooden log operates as a simple machine known as a __________.

wedge

Construction cranes use a block-and-tackle system of multiple movable pulleys to multiply lifting force by distributing load weight across multiple supporting __________ segments.

rope

A standard wing corkscrew uses a combination of a central screw, twin levers, and a __________ wheel mechanism.

rack-and-pinion

Spiral staircases function as a wrapped inclined plane, or __________ design, allowing a person to ascend with less force over a longer distance.

screw

Precision tweezers used by jewelers act as __________-class levers, where effort is applied between the fulcrum and the load.

third

A heavy wheelbarrow operates as a __________-class lever, where the load rests between the fulcrum and effort force.

second

A round door handle or doorknob is an everyday example of a __________ simple machine.

wheel and axle

Pressure is defined in physics as force applied per unit __________ perpendicular to a surface.

area

If the contact area between a pushing force and a flat surface is reduced while keeping force constant, the resulting pressure __________ proportionally.

increases

High-heeled shoes sink deeper into soft soil than flat sneakers because they concentrate body weight over a much smaller surface area, creating much higher __________.

pressure

A sharp chef's knife cuts vegetables far more effortlessly than a dull knife because its tiny surface area produces high cutting __________.

pressure

Snowshoes allow hikers to walk across deep snow without sinking because they distribute body weight over a much larger surface area, dramatically reducing __________.

pressure

Heavy construction excavators are equipped with wide caterpillar tracks to spread vehicle weight over a wide area, lowering pressure to prevent sinking into __________.

soft soil or mud

A thumbtack features a broad head to spread pushing force across your thumb and a sharp point to concentrate force on the wall, creating high __________ for easy penetration.

pressure

Pascal's Principle states that any change in pressure applied to an enclosed, incompressible fluid is transmitted __________ and undiminished to every portion of the fluid.

equally

Liquids are ideal for hydraulic systems operating under Pascal's Principle because of their near __________ under pressure.

incompressibility

In a hydraulic car lift, force applied to a small input piston transmits equal pressure to a larger output piston, producing a multiplied __________ force.

output

In a vehicle's hydraulic braking system, hydraulic fluid transmits pressure undiminished from the master cylinder to brake __________ at all wheels simultaneously.

calipers

Hydraulic systems use specialized oil rather than air because air __________ easily, leading to loss of pressure transmission and spongy movement.

compresses

When you squeeze a fully capped plastic bottle filled with water, increased fluid pressure is experienced equally throughout all regions of the water and against all interior __________ surfaces.

container

Barber chairs and dental examination chairs rise smoothly based on __________ Principle of fluid pressure transmission.

Pascal's

According to Archimedes' Principle, the upward buoyant force exerted on an object immersed in a fluid is equal to the __________ of the fluid displaced.

weight

An object placed in water will float if its overall average __________ is less than the density of water.

density

Massive steel ocean liners float on seawater because their hollow hull design displaces a large volume of water whose total weight equals or exceeds the total __________ of the ship.

weight

A submarine controls its buoyancy to submerge, hover, or surface by taking in water or pumping in air within its __________ tanks.

ballast

A hot air balloon rises into the atmosphere primarily because heated air inside expands and becomes less __________ than surrounding cooler air.

dense

A heavy submerged stone feels lighter underwater because an upward __________ force exerted by displaced water supports a portion of its weight.

buoyant

Life jackets keep swimmers afloat by adding volume filled with low-density material to displace more __________, generating high buoyant force.

water

A hydrometer operates on Archimedes' principle by measuring how deeply it sinks in a liquid sample to determine the liquid's relative density, or __________.

specific gravity

An object floats slightly __________ in salt water than in fresh water because denser salt water exerts greater buoyant force per unit volume displaced.

higher