Answer:
a) 323.4J
b) 0J
c) -323.4J
Explanation:
a) W=Fd
F=ma
solve for acc. using kinematics
v^2=vo^2+2a(x)
8.41=2a(12)
4.205=a(12)
0.35=a
F=(77)(0.35)
F=26.95N
W=26.95*12...... W=323.4J
b) No acceleration, thus no force, thus no work!
c) W=Fd
F=ma
find acc. using kinematics: v^2=vo^2+2a(x)
0=(2.9^2)+2a(12)
0=8.41+2a(12)
-8.41=2a(12)
-4.205=a(12)
-0.35=a
F=(77)(-0.35)
F=-26.95N
W=(-26.95)(12)
W=-323.4J
Yes, work can be negative!
Explanation:
We have,
Mass of an automobile is 1150 kg
The automobile traveling at 86 km/h and then it comes to stop.
86 km/h = 23.88 m/s
It is required to find work done by the automobile.
Concept used : Work energy theorem
Th change in kinetic energy of an object is equal to the work done by it. The work done is then given by :
Here, v = 0
or
Therefore, the work done by the automobile is .
You are correct. It is D. Don't make me copy it.
Try looking up the lesson and book name on the internet. then put "answer sheet"
The best answer would be a bat hitting a ball