Answer:
Variance is 25
Explanation:
Recall that the standard deviation is defined as the square root of the variance. therefore, if you know the standard deviation
, square it and you get the variance:

Answer:
B. Decrease the plane’s speed and height
Explanation:
Decrease in speed of plane:
When the speed of the plane is decreased then initial velocity of the package will be lesser. As a result, final velocity will also be lesser because in this case final velocity depends upon the initial velocity.
Decrease in height:
According to law of conservation of energy:
Loss in potential energy = Gain in Kinetic energy
mgh = ½ mV^2
It means with the decrease in height less potential energy will be converted to kinetic energy. As package has constant mass so it will gain less velocity.
Answer
given,
mass of block (m)= 6.4 Kg
spring is stretched to distance, x = 0.28 m
initial velocity = 5.1 m/s
a) computing weight of spring
k x = m g


k = 224 N/m
b) 




c) 


d) 


e)


A = 0.682 m
Force =
=
F = 94.20 N