You are standing on a skateboard, initially at rest. a friend throws a very heavy ball towards you. you can either catch the ball or deflect the ball back towards your friend (such that it moves away from you with the same speed as it was originally thrown). what should you do in order to minimize your speed on the skateboard? choose one of the following three answers.

(a) your final speed on the skateboard will be the same regardless whether you catch the ball or deflect the ball.
(b) you should catch the hall.
(c) you should deflect the ball

(B) You should catch the hall

Explanation:

B) You should catch the ball.

case 1 : when ball is catched.

Mass of person catching = M

mass of ball = m

velocity of the ball just before catching = v

velocity of ball just after catching = 0

= change in momentum of the ball = m (0 - v) = - mv

since,

case 2 : when the ball is deflected back

velocity of the ball just before catching = v

velocity of ball just after catching = - v

= change in momentum of the ball = m (- v - v) = - 2mv

since,  

clearly we can see that the change in momentum is minimum in case when the ball is catched and hence keeps the speed of skateboard minimum

the answer is f1 and d2 because if you put equal force on those two points the beam would balance trust me on this