Answer:
Explanation:
Distance = 50 m
1. To find the average speed, first start the stop watch as the sprinter starts running and then stop it when he reaches the finish line.
Now note the time taken by the sprinter to run for 50 m.
The average speed of the sprinter is defined as the ratio of total distance covered to the total time taken.
Average speed = total distance / total time
2. To find the instantaneous speed, check the seed of the sprinter as he is at the finish line.
Answer:
A and D
Explanation:
Acceleration is the active change in speed, increasing or decreasing.
Answer:

Explanation:
Total =40 miles.
y miles at x miles/hr.
40- y miles at 1.25 x miles/hr.\
We know that
Distance = time x velocity
For y miles
Lets time taken to cover y miles is t
y = x t
t=y/x -----------1
For 40- y
Lets time taken to cover 40- y is t'
40- y = 1.25 x t'
t'=(40-y)/1.25x -----------2
By adding both equation
t+t'=y/x + (40-y)/1.25x
t+t'=(32+0.2y)/x
Now lets time T taken by Marla if she will travel at x miles per hr for entire trip.
40 = x T
T=40/x
So

To find numerical value of above expression we have to know the value of y.
Answer:
a: after 1 seconds it will have fallen 0.2452
after 2 seconds it will have fallen 0.981
after 3 seconds it will have fallen 2.2072
after 4 seconds it will have fallen 3.924
Explanation:
the formula for acceleration due to gravity is (ignoring friction I think)
g = G*M/R^2
earths gravitational constant is about 9.807
g = 9.807*M/R^2
The average weight of a brick is 5 pounds and I'm going to say it's 10 feet off the ground.
g = 9.807*5/10^2. g = 0.4905 so every second the brick will go 0.4905 fps faster. (fps means feet per second.)
after 1 seconds it will have fallen 0.2452
after 2 seconds it will have fallen 0.981
after 3 seconds it will have fallen 2.2072
after 4 seconds it will have fallen 3.924