Answer: 815.51 m
Explanation:
This situation is related to projectile motion or parabolic motion, in which the initial velocity of the bullet has only y-component, since it was fired straight up. In addition, we are dealing with constant acceleration (due gravity), therefore the following equations will be useful to solve this problem:
(1)
(2)
Where:
is the final velocity of the bullet
is the initial velocity of the bullet
is the acceleration due gravity, always directed downwards
is the time
is the vertical position of the bullet at 
Let's begin by finding
from (1):
(3)
(4)
Now we have to substitute (4) in (2):
(5)
Isolating
:
This is the displacement of the bullet after 6.9 s
Answer:
a) 
b) 
c) 
d) 
e) Since Dave starts from house and finally returns to the house so displacement is zero.
Explanation:
Given:
- distance between the house and the store,

- speed of driving from house to store,

- speed of driving back from store to house,

Since the store is located towards east from his house and the velocity in this direction is taken negative and contrary to this the velocity in the west direction is taken positive.
a)
time taken in reaching the store:



b)
Now the time taken in returning form the store:



therefore total time taken by the trip:



c)
the time taken by the trip in minutes:


d)
distance travelled in the whole trip:



e)
Since Dave starts from house and finally returns to the house so displacement is zero.
I think it is C. 12 units please tell me if im wrong
Answer: D (doubled)
According to ohm's law
I = V/R ,
V = IR ; R = constant and V is doubled
From the equation
V is directly proportional to the current, and it is given that R is constant ;
2V = 2I. R since R = constant
Hence I is doubled.