BIOMECHANICS: forces (section 2)

Question 1

What is internal force?

Answer 1

a force caused by a contraction of the skeletal muscles.

Question 2

What is an external force?

Answer 2

a force applied from outside the body.

Question 3

sporting example of internal force

Answer 3

bicep contraction during a bicep curl

Question 4

sporting example of external force

Answer 4

air resistance for a cyclist

Question 5

Law of inertia

Answer 5

a body will remain in a state of uniform motion in a straight line (or at rest) unless compelled to change its state of motion by a net external force.

Question 6

law of acceleration

Answer 6

the rate of change momentum of an object is directly proportional to the force causing the change, and the resulting change in momentum takes place in a direction

Question 7

law of action and reaction

Answer 7

when one object exerts a force on a second object, the second object exerts an equal and opposite force back to the first object

Question 8

sporting example of the law of inertia

Answer 8

during a football penalty the ball (body) will remain on the spot unless it is kicked by the player (external force)

Question 9

sporting example of the law of acceleration

Answer 9

when the player kicks (force) the ball during a game the acceleration of the ball (rate of change of momentum) is proportional to the size of the force. meaning that the harder the ball was kicked the further/faster it will go.

Question 10

what is resultant force?

Answer 10

the sum of all forces acting on an object

Question 11

what is net force?

Answer 11

positive (acceleration)
negative (deceleration)
constant (inertia)