Work, Energy, Power (and Springs!)

The ability to do work or cause change:

• work

• energy

• momentum

• power

Energy in the form of motion.

• mechanical energy

• potential energy

• kinetic energy

• momentum

Stored energy in the form of position or condition.

• potential energy

• kinetic energy

• momentum

• mechanical energy

A student needs 10 Newtons of force to lift a box to the top of a 2 meter shelf. How much work do they do?

• 12 J

• 8 J

• 20 J

• 5 J

A soccer player kicks a ball with 20 Newtons of force causing it to travel 100 meters. How much work is done on the ball?

• 200 J

• 80 J

• 5 J

• 2000 J

Which of these items is not part of the law of conservation of energy?

• energy cannot be created

• energy cannot be destroyed

• energy can be transferred between forms

• energy is destroyed by friction

How much work is done in holding a 15 N sack of potatoes while waiting in line at the grocery store for 3 minutes?

• 15 J
• 45 J
• 0 J
• 5 J

What is the difference between calculating power and work?

• Power takes into account the time it takes to complete a task
• Work takes into account the time it takes to complete a task
• Power is force/area
• Work is force/area

Bob (80 kg) uses 180 N of force to get him up the slope. The vertical distance is 2 m and the diagonal is 10 m. Calculate the work he does.

• 1600 J

• 160 J

• 3600 J

• 1800 J

If F is force, k is spring constant and x is extension, Hooke's Law tells us that:

• F=k/x
• x=Fk
• k=Fx
• F=kx