Answer:
Bacteria, Hydra, Copperheads, Blackworms, and Strawberries
Explanation:
Answer:
12.7 m
Explanation:
The following data were obtained from the question:
Initial velocity (u) = 56.7 Km/hr
Maximum height (h) =..?
First, we shall convert 56.7 Km/hr to m/s. This can be obtained as follow:
Initial velocity (m/s) = 56.7 x 1000/3600
Initial velocity (m/s) = 15.75 m/s
Next, we shall determine the time taken to get to the maximum height. This can be obtained as follow:
Initial velocity (u) = 15.75 m/s
Final velocity (v) = 0 m/s
Acceleration due to gravity (g) = 9.8 m/s²
Time (t) =?
v = u – gt (since the ball is going against gravity)
0 = 15.75 – 9.8 × t
Rearrange
9.8 × t = 15.75
Divide both side by 9.8
t = 15.75/9.8
t = 1.61 secs.
Finally, we shall determine the maximum height as follow
h = ½gt²
Acceleration due to gravity (g) = 9.8 m/s²
Time (t) = 1.61 secs.
Height (h) =..?
h = ½gt²
h = ½ × 9.8 × 1.61²
h = 4.9 x 1.61²
h = 12.7 m
Therefore, the maximum height reached by the ball is 12.7 m
Let
V the speed of the girl per step
v the speed of the escalator per step
L the length between ground and floor in number of steps
V*60+v*60=L => V+v=L/60
V*90-v*90=L => V-v=L/90
By adding the equations V+v=L/60 and V-v=L/90 we get:
2V=L(3+2)/180
V=5L/360
V = L/72
Time to climb (in steps) with v=0 (escalator standing still) is:
V*t=L
t = L/V
t = L/(L/72)
t =72 steps
The girl will count 72 steps.
