Answer:
a)
Y0 = 0 m
Vy0 = 15 m/s
ay = -9.81 m/s^2
b) 7.71 m
c) 3.06 s
Explanation:
The knowns are that the initial vertical speed (at t = 0 s) is 15 m/s upwards. Also at that time the dolphin is coming out of the water, so its initial position is 0 m. And since we can safely assume this happens in Earth, the acceleration is the acceleration of gravity, which is 9.81 m/s^2 pointing downwards
Y(0) = 0 m
Vy(0) = 15 m/s
ay = -9.81 m/s^2 (negative because it points down)
Since acceleration is constant we can use the equation for uniformly accelerated movement:
Y(t) = Y0 + Vy0 * t + 1/2 * a * t^2
To find the highest point we do the first time derivative (this is the speed:
V(t) = Vy0 + a * t
We equate this to zero
0 = Vy0 + a * t
0 = 15 - 9.81 * t
15 = 9.81 * t
t = 0.654 s
At this time it will have a height of:
Y(0.654) = 0 + 15 * 0.654 - 1/2 * 9.81 * 0.654^2 = 7.71 m
The doplhin jumps and falls back into the water, when it falls again it position will be 0 again. So we can equate the position to zero to find how long it was in the air knowing that it started the jump at t = 0s.
0 = Y0 + Vy0 * t + 1/2 * a * t^2
0 = 0 + 15 * t - 1/2 * 9.81 t^2
0 = 15 * t - 4.9 * t^2
0 = t * (15 - 4.9 * t)
t1 = 0 This is the moment it jumped into the air
0 = 15 - 4.9 * t2
15 = 4.9 * t2
t2 = 3.06 s This is the moment when it falls again.
3.06 - 0 = 3.06 s
Answer:
Height h = 37.8 m
Explanation:
Given
:
Velocity of car (v) = 98 km / h
Acceleration of gravity = 9.8 m/s²
Computation:
Acceleration of gravity = 9.8 m/s²
Acceleration of gravity = (98)(1,000 m / 3,600 s)
Acceleration of gravity = 27.22 m/s
By using law of conservation of energy
;
(1/2)mv² = mgh
h = v² / 2g
h = 27.22² / 2(9.8)
Height h = 37.8 m
Answer:
A.B = -38
Explanation:
A = 2i + 9j and B = -i - 4j.
So, A.B = (2i + 9j).(-i - 4j)
= 2i.(-i) + 2i.(-4j) + 9j.(-i) + 9j.(-4j)
= -2i.i - 8i.j - 9j.i - 36j.j
since i.i = 1, j.j = 1, i.j = 0 and j.i = 0, we have
A.B = -2(1) - 8(0) - 9(0) - 36(1)
A.B = -2 - 0 - 0 - 36
A.B = -38
Need to know the equation for force
F=MA
F is force
M is mass- we need to know the mass
A is acceleration
use "x" for mass
120 N= 1.3x
divide 1.3 in both side
kg unit for mass
X=92.31 kg
or
mass = 92.31 kg
Hope this helps
D.) It is an "Element".
[ Element cannot be separated by any means ]
Hope this helps!