8th Physical Sci Sem 2 Unit 1 Work and Machines

In what direction does an applied force move an object?

• in the same direction as the force

• independent of the force

• in the opposite direction of the force

• perpendicular to the force

Which of the following is not an example of work?

• raising a barbell over your head

• picking up a box off the floor

• holding a tray in the cafeteria line

• pushing a box across the floor

What is a watt, which is a unit of power, equal to?

• a joule times a meter

• a joule divided by a meter

• a joule times a second

• a joule divided by a second

What is a joule, which is a unit of work, equal to?

• a newton times a meter

• a newton divided by a meter

• a newton times a second

• a newton divided by a second

How do simple machines make work easier?

• They add energy to the work.

• They increase the force needed to work.

• They reduce the speed of work.

• They increase the distance over which a force is applied.

If a simple machine reduces the strength of a force, what must be increased?

• the distance over which the force is applied

• the work the simple machine performs

• the speed of the input force

• the size of the simple machine

What is an input force?

• the net force on a system

• the force a person applies to a simple machine

• the applied force on a system

• the force a simple machine applies to an object

What is an output force?

• the net force on a system

• the force a person applies to a simple machine

• the applied force on a system

• the force a simple machine applies to an object

Which simple machines make up scissors?

• one lever and two wedges

• two levers and two wedges

• one inclined plane and two wedges

• two inclined planes and two wedges

Which property of potential energy distinguishes it from kinetic energy?

• mass

• shape and position

• force

• work and power