Average speed = (total distance covered) / (total time to cover the distance) .
Total distance = (80 + 50 + 40) = 170 km
Total time = (1 + 0.5 + 0.5) = 2 hours
Average speed = (170 km) / (2 hrs) = 85 km/hr .
Answer:
Your answer will be 600meters
Answer: A. Scott and Karla
Explanation: Velocity includes speed AND direction.
Opposite to the direction of the velocity which led it to its current position.
Explanation:
The direction of momentum when a vertically oscillating block comes to the rest momentarily will be opposite to the direction of the velocity that it has just followed to reach reach its current position.
The direction of change in momentum at the bottom will be upwards and at the top will be downwards.
The change in momentum is mathematically defined as:

where:
mass of the block
final velocity of the block
initial velocity of the block
When the block comes to rest it is due to the result of continuously decreasing velocity.
For an object`s motion, the Kinematic equation is,

Here, v is the final velocity and h is stands for the height of the object and a is the acceleration of the object.
As according to question,
and 
Thus, putting these values in above equation, we get

or


Therefore, initial velocity is 2.8 m/s