The video tutorial explores the concept of impact forces when stepping off a wall, comparing scenarios with and without bending knees. It introduces the impulse approximation, which assumes that during a short collision, the impact force is much larger than other forces, making them negligible. The tutorial calculates the force normal and evaluates the accuracy of the impulse approximation, revealing that bending knees results in a significant error due to a longer collision time. The video concludes that shorter collision times yield more accurate impulse approximations.

What is the approximate force of impact when knees are bent during a fall?

• 1,500 Newtons

• 5,000 Newtons

• 990 Newtons

• 11,000 Newtons

What does the impulse approximation allow us to assume during a collision?

• The force of gravity is the only force

• The net force is negligible

• The force of impact is equal to the net force

• All forces are equal

Which force acts upwards during a collision?

• Force of gravity

• Force normal

• Force of impact

• Frictional force

How is the relative error calculated in the context of impulse approximation?

• Observed value divided by accepted value

• Accepted value plus observed value

• Observed value minus accepted value divided by accepted value times 100

• Accepted value minus observed value

What is the relative error for the bent knee case using impulse approximation?

• 10%

• 0.5%

• 42%

• 6.1%