Answer:a
Explanation:
We have to lift the load two loads up one story, so energy required is
let m be the mass of each load and h is the height of each story
Energy 

Here energy gained is the potential energy which depends upon the datum(floor).
For lifting one load up one story
Energy required

thus
is half of 
So option a is correct
Given :
The average acceleration of a tennis ball that has an initial velocity of 6.0 m/s.
and a final velocity of 7.3 m/s.
It is in contact with a tennis racket for 0.094 s
To Find :
The average acceleration of the tennis ball.
Solution :
We know, average acceleration is given by :

Therefore, average velocity is given by 13.83 m/s².
Hence, this is the required solution.
Answer:
The rate of change of distance is defined as speed.
Explanation:
The speed is defined as the rate of change of distance.
Speed = distance/ time
When we know the distance and the time, we get the value of speed. So, e know that who is moving fast or slow.
hen a graph is pltted beteen the distance and time, the slope of the graph gives the value of speed. So, by checking the slopes, hoseslope ismore, the speed is more and thusit is moving faster.
So, i agree with the statement.