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).
the awnser to ur question is D
Answer:
3.5 hours
Explanation:
Speed = distance/time
Let the distance that Fiora biked at 20 mi/h through be x miles and the time it took her to bike through that distance be t hours at 20 mi/h
Then, the rest of the distance that she biked at 14 mi/h is (112 - x) miles
And the time she spent biking at 14 mi/h the rest of the distance = (6.5 - t) hours
Her first biking speed = 20 mph = 20 miles/hour
Speed = distance/time
20 = x/t
x = 20 t (eqn 1)
Her second biking speed = 14 mph = 14 miles/hour
14 = (112 - x)/(6.5 - t)
112 - x = 14 (6.5 - t)
112 - x = 91 - 14t (eqn 2)
Substitute for x in (eqn 2)
112 - 20t = 91 - 14t
20t - 14t = 112 - 91
6t = 21
t = 3.5 hours
x = 20t = 20 × 3.5 = 70 miles.
(112 - x) = 112 - 70 = 42 miles
(6.5 - t) = 6.5 - 3.5 = 3 hours
Meaning that she travelled at 20 mi/h for 3.5 hours.
Answer:
the air has to be unstable as well as it needs to be moved upwards.
Explanation:
it needs to be moved upwards and also needs to have unstable air.
