Answer:
The force on the ball is the same
it depends ether people can give you hope or you can have hope
Explanation:
2000Hz and 1500Hz
Using
a) f = f0((c+vr)/(c+vs))
=>>> f0((c)/(c-0.5c))
=>>>1000/0.5 = 2000Hz
b) f = f0((c+vr)/(c+vs))
=>>>f0((c+0.5c)/(c))
=>>>>1000 x 1.5 = 1500Hz
