Answer:
7,79 seconds
Explanation:
You need to use the acceleration formula. A is acceliration, 
is change in velocity and t is time.
You need to multiply the formula with t and divide by a and you get
a*t=
t= /a
after that you just need to insert the numbers
change in velocity is 76.4 minus 0.
acceliration is gravitational acceleration which is 9.81.
After that you get
t=76.4/9.81
t= 7,787971458 s
Answer:
its C. The north pole of one magnet attracts the south pole of another
Explanation:
I JUST TOOK THE TEST
<span>When the fuel of the rocket is consumed, the acceleration would be zero. However, at this phase the rocket would still be going up until all the forces of gravity would dominate and change the direction of the rocket. We need to calculate two distances, one from the ground until the point where the fuel is consumed and from that point to the point where the gravity would change the direction.
Given:
a = 86 m/s^2
t = 1.7 s
Solution:
d = vi (t) + 0.5 (a) (t^2)
d = (0) (1.7) + 0.5 (86) (1.7)^2
d = 124.27 m
vf = vi + at
vf = 0 + 86 (1.7)
vf = 146.2 m/s (velocity when the fuel is consumed completely)
Then, we calculate the time it takes until it reaches the maximum height.
vf = vi + at
0 = 146.2 + (-9.8) (t)
t = 14.92 s
Then, the second distance
d= vi (t) + 0.5 (a) (t^2)
d = 146.2 (14.92) + 0.5 (-9.8) (14.92^2)
d = 1090.53 m
Then, we determine the maximum altitude:
d1 + d2 = 124.27 m + 1090.53 m = 1214.8 m</span>
