Answer:
t = 1.068 s
Step-by-step explanation:
given,
a(t) =- k v(t)
speed of the object decreases from 800 ft/s to 700 ft/s
distance = 1400 ft
time for deceleration = ?
a(t) =- k v(t)
integrating both side
..........(1)
since,
from equation 1
putting value of k in equation (1)
t = 1.068 s
Answer:
There are 118 plants that weight between 13 and 16 pounds
Step-by-step explanation:
For any normal random variable X with mean μ and standard deviation σ : X ~ Normal(μ, σ)
This can be translated into standard normal units by :
Let X be the weight of the plant
X ~ Normal( 15 , 1.75 )
To find : P( 13 < X < 16 )
= P( -1.142857 < Z < 0.5714286 )
= P( Z < 0.5714286 ) - P( Z < -1.142857 )
= 0.7161454 - 0.1265490
= 0.5895965
So, the probability that any one of the plants weights between 13 and 16 pounds is 0.5895965
Hence, The expected number of plants out of 200 that will weight between 13 and 16 = 0.5895965 × 200
= 117.9193
Therefore, There are 118 plants that weight between 13 and 16 pounds.