Answer:
The required angle is (90-25)° = 65°
Explanation:
The given motion is an example of projectile motion.
Let 'v' be the initial velocity and '∅' be the angle of projection.
Let 't' be the time taken for complete motion.
Let 'g' be the acceleration due to gravity
Taking components of velocity in horizontal(x) and vertical(y) direction.
= v cos(∅)
= v sin(∅)
We know that for a projectile motion,
t =
Since there is no force acting on the golf ball in horizonal direction.
Total distance(d) covered in horizontal direction is -
d =
×t = vcos(∅)×
=
.
If the golf ball has to travel the same distance 'd' for same initital velocity v = 23m/s , then the above equation should have 2 solutions of initial angle 'α' and 'β' such that -
α +β = 90° as-
d =
=
=
=
.
∴ For the initial angles 'α' or 'β' , total horizontal distance 'd' travelled remains the same.
∴ If α = 25° , then
β = 90-25 = 65°
∴ The required angle is 65°.
Answer;
D. rocket engines are not dependent on oxygen from the air.
Explanation;
-Jet engines and rockets work on the same principle. They produce thrust through an internal pressure difference and, as explained by Newton’s Third Law of Motion, eject exhaust gases in an equal and opposite direction.
-The main difference between them is that jets get the oxygen to burn fuel from the air and rockets carry their own oxygen, which allows them to operate in space.
Additionally, Jet engines have two openings (an intake and an exhaust nozzle). Rocket engines only have one opening (an exhaust nozzle).
The electric potential energy of the pair of charges when the second charge is at point b is U at b = +7.3×10⁻⁸J.
Electric potential is the amount of work done in moving point charge from infinity to aspecific point.
Calculation of the electric potential energy:
Here the particle should be moved from the point at the time when the potential energy should be U a
The U b should be the change in the potential energy
W is work done.
(W at a )-(W at b) = U a - U b
U b = U a - (W at a )+(W at b)
So,
= 5.4 × 10⁻⁸J - ( -1.9×10⁻⁸ J)
= +7.3×10⁻⁸J.
Learn more about electric potential here:
brainly.com/question/24284560
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Answer:
The value 
Explanation:
From the question we are told that
The acceleration due to gravity is a = 2g
The maximum height is h= 39 m
Generally from the kinematic equation

Here u is the velocity of the ball at maximum height before it start falling and the value is 0 m/s
So



