A rigid ball of mass m strikes a rigid wall at ${60}^{°}$ and gets reflected without loss of speed as shown in the figure. The value of impulse imparted by the wall on the ball will be 

(1) mv

(2) 2mv

(3) mv/2

(4) mv/3

A bullet of mass 10g moving horizontal with a velocity of 400 m/s strikes a wood block of mass 2 kg which is suspended by light inextensible string of length 5 m. As result, the centre of gravity of the block found to rise a vertical distance of 10 cm. The speed of the bullet after it emerges of horizontally from the block wiil be 

(1) 100 m/s 

(2) 80 m/s

(3) 120 m/s 

(4) 160 m/s 

A rigid ball of mass M strikes a rigid wall at ${60}^0$ and gets reflected without loss of speed, as shown in the figure. The value of the impulse imparted by the wall on the ball will be:
      

1.  Mv

2.  2Mv

3.  Mv/2

4.  Mv/3