L3 - Intro to impacts (part 3)

Question 1

The effect of mass on swing velocity (experiment)

Daish (1964) – experiment looking at relationship between club _____ _____ and the ______ of golf shot.

 Sample of different golfers with different physical and golfing ability
 Variable club head mass (brass discs)
 Average swing vel. measured with light gate

what is the linear relationship between club mass and swing Vel. ?

Answer 1

head mass, distance

MV^n = constant ‘C’

n, slope of the line . This case , all lines have roughly the same slope.

Question 2

The effect of mass on swing velocity

What is the initial velocity, v, imparted to the ball by clubhead (mass ,M. velocity, V)?

eliminate V in the eqaution

Answer 2

Question 3

The effect of mass on swing velocity

How do you find the value for M which yields the maximum v’ ?

Hence, find M when the mass of the golf ball m = 49 grams and n = 5.3 (from the experiment)

Answer 3

Question 4

The effect of mass on swing velocity (results)

There is no evidence to suggest that a powerful player should use ______ clubs or the ______. Optimum club head mass is ___ _____ for strong and weak subjects.

o Equation (11) relates the initial velocity imparted to the ball with the mass of the club head used.
  constant ,C, in the equation depends the individual striker
 • it is \_\_\_\_\_\_\_\_ for a more powerful player.

 An arbitrary value of C can be chosen to give an initial ball velocity of 70 ms-1 using an optimum mass of clubhead of 200 g
 Velocities to be expected using club heads of different ______ can then be calculated using the same value of _ .

Answer 4

heavier, reverse

the same ,

greater

masses

C

Question 5

The effect of mass on swing velocity (results)

 The results displayed in Fig. 5.

o The dotted line shows the launch velocity to be expected (if the swing velocity is _ ______), as previously shown in Fig. 3 for a coefficient of restitution of 0.7.

o The solid line, however, shows what appears to happen in _______ if the swing velocity _____ with ___ ____ as shown in Fig. 4.

 The graph shows there is only a very ____ ______in ball velocity expected from wide range of club head masses.

o Over the range from ___ to ____ g, the velocity of the ball remains almost constant.

Answer 5

a constant,

practice, reduces

club mass

small variation

150 - 300

Question 6

The effect of mass on swing velocity

(Intro to impact conclusions)

• _____ ________ can be used to approximate a sports ball impact
• As the ____ of a golf club head increases, the efficiency _______
• As the ___ of the club head increases, the momentum transferred to the ball _____ and the ball is launched _____
• The player swings _____ as the mass increases. Thus, the two cancel out to give a ____ ______ launch velocity regardless of ____ _____.

Answer 6

simple equations

mass

decreases

incresaes

mass

slower

near constant

club mass