Answer:

Explanation:
Given that the airplane starts from the rest (this is initial velocity equals to zero) and accelerates at a constant rate, position can be described like this:
where x is the position, t is the time a is the acceleration and
is initial velocity. In this way acceleration can be found.
.
Now we are able to found velocity at any time with the formula: 
Answer:
if the frequency is double, the wavelength is only half as long
Explanation:
Let's assume that Zoey ran at a constant speed. we can use the equation,
d = st
where, d = distance, s = speed, and t = time taken.
By rearranging,
s = d/t
Zoey had travelled 100 m in 20 seconds.
Hence, s = 100 m / 20 s = 5 m/s
therefore Zoey's speed at 100 m is 5 m/s
Answer:
60 km
Explanation:
For an object (or a person, such as in this case) moving at constant speed, the speed is equal to the ratio between the distance travelled and the time taken:
where
v is the speed
d is the distance
t is the time taken
In this case, we have:
v = 120 km/h is the speed
t = 30 min = 0.5 h is the time taken
Therefore, we can rearrange the equation to find the total distance travelled: