Why We Use Machines

Why We Use Machines - Transcript

Why we use machines Why

Machine device that makes
work easier work 2 forces are involved when forces machine is used machine 1 Effort force Fe The force applied to the machine applied 2 Resistance force Fr The force applied by the machine

Ex You apply effort force to a crowbar handle The crowbar handle has resistance force on lid to crate lid

There s 2 kinds of work when a machine is used machine 1 Work input Win Work done on the machine done 2 Work output Wout Work done by the machine done

To calculate Work input
Win Fe X de Win Win effort force X distance Win To calculate Work output Wout Fr X dr Wout resistance force x Wout distance distance

Work output can never be greater than Work input It will always be a smaller number than Work input than

Ideal machine machine in
which work input equals work output output W in W out Fe X de Fr X dr

Mechanical Advantage MA the number of times a machine multiplies the effort force The higher the MA the easier The it is on you it

To calculate the mechanical To
advantage of any machine advantage Variable Ending Units Variable Ending Effort force Fe Newton Resistance force Fr Newton Newton Mechanical Advantage None Mechanical MA

MA Fr Fe Fr MA x Fe Fe Fr MA


Fr



MA x Fe

To find the mechanical To
advantage of a lever advantage MA Length of effort arm MA length of resistance arm length MA Le Lr MA 30m 10m MA 3

To find the mechanical To
advantage of a wheel and axle advantage MA radius of wheel radius of MA axle axle
MA 5 1 MA MA 5

To find the mechanical To
advantage of an inclined plane plane MA Length of slope Height MA of slope of

To find the mechanical advantage To
of a pulley of MA Number of pulleys you see

MA 1 MA 5

MA 4

MA 2