What the dog doin? Legend says, no one has ever known what the dog has been doing.
1 answer:
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Answer:
acceleration 8 km/h/s south
Explanation:
First of all, let's remind that a vector quantity is a quantity which has both a magnitude and a direction.
Based on this definition, we can already rule out the following two choices:
distance: 40 km
speed: 40 km/h
Since they only have magnitude, they are not vectors.
Then, the following option:
velocity: 5 km/h north
is wrong, because the car is moving south, not north.
So, the correct choice is
acceleration 8 km/h/s south
In fact, the acceleration can be calculated as
where
v = 40 km/h is the final velocity
u = 0 is the initial velocity
t = 5 s is the time
Substituting,
And since the sign is positive, the direction is the same as the velocity (south).
Answer:
(a) r = 1.062·R =
(b) r =
(c) Zero
Explanation:
Here we have escape velocity v given by
and the maximum height given by
Therefore, when the initial speed is 0.241v we have
v = so that;
v² =
v² =
is then
Which gives
or
r = 1.062·R
(b) Here we have
Therefore we put in the maximum height equation to get
From which we get
r = 1.32·R
(c) The we have the least initial mechanical energy, ME given by
ME = KE - PE
Where the KE = PE required to leave the earth we have
ME = KE - KE = 0
The least initial mechanical energy to leave the earth is zero.