Acar of mass 650 kg slows from a speed of 20.0 m/s to a speed of 10.0 m/s. how much kinetic energy has it lost. how much force is required to do this over a distance of 97.5

Formulas you need for this problem:
F= mass•acceleration
KE= mass•velocity^/2
Acceleration= final velocity-intial velocity/time
time= distance/speed

t= 97.5\10= 9.75 seconds
Acc= 10-20/9.75= -1.03 m/s/s

These are the answers :)
F=650•-1.03= -669.5N
KE= 650•100/2= 32,500J or 32.5KJ

B)The decrease in atmospheric pressure relative to pressure inside the balloon causes it to expand.