Question

A bicycle and its rider have a combined mass of 80.0 kilograms and a speed of 6.0 meters per second. What is the magnitude of the average force needed to bring thebicycle and its rider to a stop in 4.0 second?
1.9 103 N
3.2 102 N
4.8 102 N
1.2 102 N

Answer 1

Answer 2

a= F/masstotal

vf=Vi+at
0=6+F/80 * 4

solve for F.

Answer 3

[delete]

Answer 4

[delete]

Answer 5

retardation= ( 6-0)/ 4= 1.5 m/s^2

Force required = ma = 80(1.5)= 1. 2 x 10^{2 N}