Q1. A hare and a tortoise compete in a race over the course 3.15 km long. The tortoise crawls straight and steadily at its maximum speed of 0.830 m/s toward the finish line. The hare runs at its maximum speed of 6.30 m/s toward the goal for 0.800 km and after that stops to tease the tortoise. How close to the goal can the hare let the tortoise approach before resume the race, which the tortoise wins in photo finish? Suppose that, when moving, both animals move steadily at their respective maximum speeds. How to work this problem?

Q2. Two cars were firstly at rest and side-by-side between two photogates. The mass of cart 1 was 0.505kg. The spring was activated and two carts moved away from one another, passing through the photogates and producing the readings as shown below. Find out the mass of cart 2?