Catching up with walking sister · PhysicsBowl 2025 #1
Physics · mechanics
Problem
Your sister is 50 m ahead of you and walking at a speed of 1 m/s away from you. You run to catch up to her at a speed of 2.5 m/s. How much time does it take for you to catch her?
a. 14 s
b. 20 s
c. 33 s
d. 72 s
e. 125 s