Elastic Potential Energy and Spring Forces

The video tutorial explains elastic or spring potential energy, starting with a review of Hooke's Law. It covers the calculation of work done by springs using average force and derives the spring potential energy formula. The tutorial also demonstrates the calculus approach to spring energy equations. Two example problems are solved: one involving an archer pulling a bowstring and another analyzing Rod Kimble's moped scenario using energy principles.

What is the relaxed length of a spring?

• The length when the spring is under maximum tension

• The length when the spring is fully stretched

• The length when the spring is fully compressed

• The length when the spring is neither compressed nor stretched

According to Hooke's Law, what does the spring force depend on?

• The temperature of the environment

• The velocity of the object attached to the spring

• The change in position from the spring's relaxed length

• The mass of the object attached to the spring

How is the average force of a spring calculated?

• By multiplying the initial and final forces

• By dividing the final force by the initial force

• By adding the initial and final forces and dividing by two

• By subtracting the initial force from the final force

What is the relationship between work done by a spring and its potential energy?

• Work done is always positive

• Work done is unrelated to potential energy

• Work done is equal to the decrease in potential energy

• Work done is equal to the increase in potential energy

In the calculus method, what is integrated to find the spring potential energy?

• The mass of the object

• The velocity of the object

• The force of the spring over the change in position

• The spring constant

What does the term 'elastic' refer to in elastic potential energy?

• The ability of an object to change color

• The ability of an object to absorb sound

• The ability of an object to return to its original shape

• The ability of an object to conduct electricity

In the archer and bow example, what is the spring constant if the force is 140 N and the displacement is 0.7 m?

• 200 N/m

• 140 N/m

• 240 N/m

• 100 N/m

How much elastic potential energy is stored in the bow when the string is pulled back 0.7 meters with a spring constant of 200 N/m?

• 24.5 Joules

• 49 Joules

• 70 Joules

• 100 Joules

In the spring-loaded cannon example, what is the initial height used for calculating potential energy?

• 100 meters

• 70 meters

• 10 meters

• 80 meters

What is Rod's final velocity when he goes off the ramp in the spring-loaded cannon example?

• 57.5 m/s

• 27.5 m/s

• 37.5 m/s

• 47.5 m/s