Bio mech

Question 1

Explain how a gymnast can alter the speed of rotation (angular velocity) during flight.

Answer 1

1. Changing the shape of the body causes a change in speed
2. Change in the moment of inertia leads to a change of angular velocity/speed/spin of rotation.
3. Angular momentum remains constant (during rotation)
4. Angular momentum = moment of inertia x angular velocity
5. Angular momentum - the quantity of rotation/motion
6. Angular velocity - the speed of rotation
7. Moment of inertia - spread/distribution of mass around axis/reluctance of the body to move
8. To slow down (rotation) gymnast increases the moment of inertia Achieved by extending body/opening out/or equivalent
9. To increase speed (of rotation) gymnast decreases the moment of inertia. Achieved by tucking body/bringing arms towards the rotational axis

Question 2

What type of graph is this?

A. Distance /Time

B. Velocity/ time

C. Speed/time

D. None of the above.

Answer 2

A. Distance /Time