Explanation:
for v vs t graph for t=9 to 11,v=15kmph
similarly v2=0,v3=60kmph&v4= -40kmph
As this happens over twelve seconds, you would take the total difference in velocities and divide it by twelve to find the change per second
44.0 m/s - 2.0 m/s = 42.0 m/s
42.0 m/s / 12 s = 3.5 m/s2
the acceleration of the rock would be 3.5 m/s2
Acceleration occurs whenever the direction or the speed changes
Answer:

Explanation:
The correct equation follows the law of conservation of energy where kinetic energy is all transformed to potential energy, since we know that kinetic energy is expressed as
while potential energy is mgh where m is the mass of the object, v is the velocity or speed of the object, g is acceleration due to gravity and h is the vertical height. Therefore, relating the two equations we should have 