You are walking a dog when the dog sees a cat and runs away from you. You immediately run after the dog at 4.90 m/s. You jump at an angle of 30.0° to try and catch the dog. While you are in the air the dog is able to move an extra 1.72 m away from you. If you are able to land on the dog, how fast must the dog have been running if it was running at a constant speed in a straight line?

1 answer

How long were you in the air?

v sinθ t - 4.9t^2 = 0

So, the dog's speed is 1.72/t

This assumes that at t=0 you and the dog were in (approximately) the same spot.