• Work
• Time
• Force
• All of above
• #### 2.  When you rub your hands together on a cold day, you use friction to convert

• Mechanical energy into thermal energy
• Thermal energy into nuclear energy
• Chemical energy into mechanical energy.
• Electrical energy into thermal energy

• 200 J
• 80 J
• 5 J
• 2000 J

• 600 J
• 450 J
• 900 J
• 1200 J

• 272 m
• 17 m
• 4.05 m
• 272 cm

• 160 watts
• 10 watts
• 6.4 watts
• 17 watts
• #### 7.  This picture shows an example of what type simple machine?

• pulley
• wedge
• lever
• wheel and axle
• #### 8.  The sun provides ____________ and ____________ energy that can be harnessed and used for solar power.

• chemical, sound
• mechanical, light
• sound, light
• light, thermal

• mechanical
• thermal
• kinetic

• 30 watts
• 3 watts
• 120 watts
• 270 watts
• #### 11.  Which statement illustrates work done?

• A weightlifter holds a barbell above her head.
• A teacher applies a continuous force to a book, holding it flat.
• A student flicks a paper football and moves it over the edge of a table.
• A waiter carries a tray full of meals while listening to a customer.
• #### 12.  How can you decrease the effort force needed to push a weight to the top of the ramp?

• cover the surface with carpet
• increase the length of the ramp
• increase the height of the ramp
• decrease the length of the ramp

• A
• B
• C
• D
• #### 14.  The amount by which a machine multiplies input force is known as the

• work.
• power.
• output force.
• #### 15.  A student with a mass of 62 kg walks up a flight of stairs with a height of 3.4 meters. How can he decrease his power?

• walk slower
• walk faster
• carry his friends books
• All of above
• #### 16.  A roller coaster whose average speed is 32 m/s is at the top of a 72m hill and weighs 966N. At the top of the hill the coaster car has ___________________ energy.

• almost all kinetic energy
• almost all potential energy
• mostly kinetic energy
• some kinetic and some potential energy

• 2.5 m
• 3.5 m
• 0.4 m
• 25 m

• 100 watts
• 400 watts
• 104 watts
• 50 watts
• #### 19.  Simple machines make work easier by increasing what?

• The distance over which work is done
• The force needed to do work
• The time required to do work
• The acceleration of a massive object
• #### 20.  This is energy that is stored for later use.

• kinetic energy
• potential energy
• mechanical energy
• #### 21.  What type of simple machine is a bike pedal?

• Inclined Plane
• Pulley
• Wedge
• Lever
• #### 22.  Light is an example of _________

• thermal energy