Net force is basically the force an object has when changing direction, so the answer would be D.
net force= the sum of all the forces acting on the object
the frictional force is opposite to the direction of motion of the object
If the object moves to the right (positive) then the friction force moves to the left (negative).
so the net force: 50 N - 5 N = 45 N (B)
125 because f=ma so you would use 100=mx0.75
To calculate the final velocity, we use Newton's first equation of linear motion:v=u+at
Where v is final velocity
u is initial velocity
a is the average acceleration
t is the time taken during acceleration.
Therefore,
v=0+2.5m/s²*6.00s
=15m/s
Decelerating from 15m/s;
v=15m/s+(-2m/s²×4.0s)
=3m/s
To get the distance it travelled, we use
v²=u²+2as
During acceleration, the distance travelled is calculated as below.
15²=0+2×2.5S
225=5S
S=45meters
During decellaration, displacement is calculated as below,
3²=15²+(2×4S)
9=225+8S
8S=216
S=27meters
Total displacement=45m+27m
=72 meters.