Answer:
a)8.59 m/s
b)-0.8818 m/s²
Explanation:
a) Given the van moved 40 m in 7.70 seconds to a final velocity of 1.80 m/s
Apply the equation for motion;
where
t=time the object moved
d=displacement of the object
Vi=initial velocity
Vf=final velocity
Given
t=7.70s
Vf=1.80 m/s
d=40m
Vi=?
Substitute values in equation
b)Acceleration is the rate of change in velocity
Apply the formula
Vf=Vi+at
where;
Vf=final velocity of object
Vi=Initial velocity of the object
a=acceleration
t=time the object moved
Substitute values in equation
Given;
Vf=1.80 m/s
Vi=8.59 m/s
t=7.70 s
a=?
Vf=Vi+at
1.80=8.59+7.70a
1.80-8.59=7.70a
-6.79=7.70a
-6.79/7.70=7.70a/7.70
-0.8818=a
The van was slowing down.