science

What two things must happen for work to be done

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• 1. If the force and motion are parallel, the work done is force times the distance. 

• What two things must happen for work to be done ? applied force must make the

• 1. Increase the force of an object increase the distance over which a force is applied changing the direction of an applied force 

1. When force is perpendicular to motion, the work done is zero.

• 1. because a machine produces friction, the output work less than the input work

• 1. Increase the force of an object increase the distance over which a force is applied changing the direction of an applied force 

• If the force and motion are parallel, the work done is force times the distance. 

• 1. applied force must make the object move. The object must move in the direction of the applied force

1. Name three ways that machines make work easier.

• 1. If the force and motion are parallel, the work done is force times the distance. 

• Increase the force of an object increase the distance over which a force is applied changing the direction of an applied force 

• 1.  because a machine produces friction, the output work less than the input work

• 1. applied force must make the object move. The object must move in the direction of the applied force

1. Why is the efficiency of a machine always less than 100% ?

• 1. If the force and motion are parallel, the work done is force times the distance. 

• 1. Increase the force of an object increase the distance over which a force is applied changing the direction of an applied force 

• 1. applied force must make the object move. The object must move in the direction of the applied force

• because a machine produces friction, the output work less than the input work

1. To increase speed the force must be

• change

• 1. reduced

• 1. mass and speed 

• form

1. Anything that causes ____ must have ____ .

• chnage,energy

• force,light

• reaction,darkness

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1. What unit is used to measure energy ?

• clorine (c)

• 1. Joule (J)

• mass

• energy

Lifts four forms of energy discussed in Section 2.

• Electrical , chemical, radiant, and thermal 

• mass,air,resistance,mass

• just energy

• all of the above

1. What two things affect kinetic energy of a moving object ?

• mass and speed 

• air,water

• force,motion

• all of the above

1. Gravitational potential energy depends on what two things ?

• air resistance,force,air

• none of these

• mass, acceleration of gravity and height 

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