Two nuclei have mass number in the ratio of 2:5 what is the ratio of their number densities

Aspacecraft that renters the earth’s atmosphere drastically slows down. the amount of kinetic energy the spacecraft has as it reenters the earths atmosphere

Aprotein molecule in an electrophoresis gel has a negative charge. the exact charge depends on the ph of the solution, but 30 excesselectrons is typical. what is the magnitude of the electric forceon a protein with this charge in a 1500 n/c electric field?

Atortoise and hare start from rest and have a race. as the race begins, both accelerate forward. the hare accelerates uniformly at a rate of 1.3 m/s2 for 4.5 seconds. it then continues at a constant speed for 12.5 seconds, before getting tired and slowing down with constant acceleration coming to rest 99 meters from where it started. the tortoise accelerates uniformly for the entire distance, finally catching the hare just as the hare comes to a stop. 1) how fast is the hare going 1.8 seconds after it starts? see solution 2.34 m/s your submissions: 2.34 computed value: 2.34submitted: saturday, january 19 at 3: 34 pm feedback: correct! 2) how fast is the hare going 9.1 seconds after it starts? see solution 5.85 m/s your submissions: 5.85 computed value: 5.85submitted: saturday, january 19 at 3: 35 pm feedback: correct! 3) how far does the hare travel before it begins to slow down? see solution 86.29 m your submissions: 86.29 computed value: 86.29submitted: saturday, january 19 at 3: 46 pm feedback: correct! 4) what is the acceleration of the hare once it begins to slow down? see solution -1.34 m/s2 your submissions: -1.34 computed value: -1.34submitted: saturday, january 19 at 3: 47 pm feedback: correct! 5) what is the total time the hare is moving? see solution 21.37 s your submissions: 21.37 computed value: 21.37submitted: saturday, january 19 at 3: 49 pm feedback: correct! 6) what is the acceleration of the tortoise?