Help plz i dont know what to do

A100 kg running back runs at 5m/s into a stationary linebacker. it takes 0.5 for the running back to be completely stopped

Question 11 of 13 (1 point) jump to question: a stairway, ladder, or ramp must be present in excavations in which of the following situations? a. all trenches must have access/egress b. the trench is more than 15 feet wide but only 1 ½ feet deep c. the trench is more than 4 feet deep and the devices must be within 25 feet of all workers

The ability to make things happen is also called a. heat b. force c. matter d. energy