My book has the answers. Can someone show me the steps?
A tennis ball of mass m = 0.06 kg and speed v = 25 m/s strikes a wall at a 45° angle and rebounds with the same speed at 45° What is the impulse given the wall?
The answer is: Magnitude= 2.1 N*s
2007-03-25 07:59:06 · 3 answers · asked by beast 1 in Science & Mathematics ➔ Physics
mV_1 = mV_2 +impulse
The velocitys are vectorial
mV_1 - mV_2 = 2 mV_1 cos 45 =2*0.06*25*cos45=2.1213 N.s
2007-03-25 08:34:40 · answer #1 · answered by santmann2002 7 · 0⤊ 0⤋
Here we're talking of impulse given to the wall, and it is measured at right angles to the wall. So the speed has to be reduced to the speed perpendicular to the wall, namely,
25 m/s * sin(45)=17.68 m/s
Since the ball bounces from the wall after impact, the velocity then is negative.
Change in velocity=-17.68+17.68=35.36
mass=0.06 kg
Impulse=35.36*0.06=2.12 N s
2007-03-25 08:07:35 · answer #2 · answered by mathpath 2 · 0⤊ 0⤋
J = m (Vf - Vi)
break the velocity into x-component
cos(45)25 = 17.68m/s
assume the ball moves to the right and bounces back. The final velocity is -17.68m/s
J = .06 (-17.68 - 17.68)
J = - 2.12 N*s
the negative means the impulse is in opposite direction
2007-03-25 08:08:55 · answer #3 · answered by 7 · 0⤊ 0⤋