Posted by Mel on Sunday, November 20, 2011 at 6:04pm.
A tennis ball of mass= 0.058 kg and speed= 19 m/s strikes a wall at a 45 degree angle and rebounds with the same speed at 45 degrees.
What is the magnitude of the impulse given to the ball?

PHYSICS PLEASE HELP!!  drwls, Sunday, November 20, 2011 at 6:18pm
Only the momentum component perpendicular to the wall changed.
The change,
2M*V cos 45,
equals the impulse given 
A man wants to cross a river 500 m wide which flows at speed of 2 km/hr.the man rows a boat perpendicular to the river flow at 3 km/hr relative to the river.what is relative velocity of boat relative to the ground?  Physics, Thursday, January 12, 2012 at 12:39pm
Velocity of boat relative to the river(vbr):3 km/hr, velocity of river relative to ground(vrg) :2 km/hr. Velocity of boat relative to the ground(vbg): square root of 9+4