i dont understand wat im doing wrong here is my problem Choose the positive direction to be from the pitcher to the plate (some answers may be negative). A pitcher throws a 0.13 kg baseball so that it crosses home plate horizontally with a speed of 31 m/s. It is hit straight back at the pitcher with a final speed of 28 m/s. What is the impulse delivered to the ball? Answer in units of kg m/s Find the average force exerted by the bat on the ball if the two are in contact for 0.0011 s. Answer in units of N ok here is my work Impulse=m(vf-vi) .13(28-31)=-.39 then for average force i have I=t*af -.39=.0011*af af=-354.5454545 but i change my signs to positive right?? either way my answer is wrong help please
the problem asks you to consider pitcher to batter as the positive direction, thus, batter to pitcher is the negative direction. What is the direction of vf? once you correct the value of impulse, your force will be correct and it will ahve a minus sign associated with it. What does the minus sign indicate about the direction of the force of the bat on the ball?