Work and Machines

1. Work and Machines

2. 9 Seconds Remaining Work equals Force times • Energy • Velocity • Distance • Mass

3. 0 Seconds Remaining Work is measured in • Meters • Pounds • Joules • Newtons

4. Work and Machines Describe what a machine is and how it makes work easier to do. Relate the work input to a machine to the work output of the machine.

5. 0 Seconds Remaining Which of these is an example of work being done on an object? • Holding a heavy piece of wood at a construction site. • Trying to push a car that doesn’t move out of deep snow. • Pushing a child on a swing. • Holding a door shut on a windy day so it doesn’t blow open.

6. Machines Do Work • A Machine is a device that changes force. • Machines make work easier to do in three ways. • Change the size of a force needed. • Direction of a force • Distance over which a force acts.

7. 0 Seconds Remaining What do machines do? • Change the amount of force you exert or the distance over which you exert the force. • Increase the amount of work that is done. • Decrease the amount of work that is done. • Eliminate friction.

8. Increasing Force • The upward force exerted by the jack is greater than the downward force you exert of the handle.

9. Increasing Distance • They will do the same amount of work. Doing the work over a longer distance allows them to use less force.

10. Changing Direction • When you use an ax to split wood, you exert a downward force as you swing the ax then it changes into a horizontal force that splits the wood apart.

11. 0 Seconds Remaining How can a hockey stick be considered a machine? • It multiplies force. • It multiplies distance. • It changes direction. • It reduces friction.

12. 0 Seconds Remaining Pulling down on a rope to hoist a sail on a sailboat is an example of a machine. • Multiplying the force you exert. • Multiplying the distance over which a force is exerted. • Changing the direction in which a force is exerted. • Reducing friction.

13. Input Force • The force that you apply to the machine. • It is also known as the Effort Force.

14. Output Force • The force that is applied by the machine. • It is also known as the Resistance Force.

15. 0 Seconds Remaining A term that means the same thing as output force is • Input force • Resistance force • Effort force • Multiplying force