Answer:
The rate of change of the shadow length of a person is 2.692 ft/s
Solution:
As per the question:
Height of a person, H = 20 ft
Height of a person, h = 7 ft
Rate = 5 ft/s
Now,
From Fig.1:
b = person's distance from the lamp post
a = shadow length
Also, from the similarity of the triangles, we can write:

Differentiating the above eqn w.r.t t:
Now, we know that:
Rate = 
Thus
Answer:
-30m/s
Explanation:
Given:
Initial velocity of object = 200 feet/second
Final velocity of object = 50 feet/second
Time of travel = 5 seconds
To calculate acceleration of the object we will find the rate of change of velocity with respect to time.
So, acceleration "a" is given by:

where vf represents final velocity, vi represents initial velocity and is time of travel.
Plugging in values to evaluate acceleration.



The acceleration of the object is -30m/s
Answer:
the ans is D... good luck
To calculate instantaneous speed, we need to divide part of the total distance traveled by time. However, we don't want to use the distance of the entire trip, because that will give us average speed.
Answer:
Acceleration, 
Explanation:
Given that,
Mass of the planet Krypton, 
Radius of the planet Krypton, 
Value of gravitational constant, 
To find,
The acceleration of an object in free fall near the surface of Krypton.
Solution,
The relation for the acceleration of the object is given by the below formula as :



So, the value of acceleration of an object in free fall near the surface of Krypton is 