As you can see in the image Im having trouble answering this

As you can see in the image, I\'m having trouble answering this one. I looked back at it and I now understand where I went wrong on problem 1. Acceleration is going to be g. However, I have tried to solve question 3 several times, and I\'m just not understanding where I went wrong or how to start off in the right direction.

Solution

Here ,

as the acceleration of the object is same on all the points and it is due to gravity

the acceleration of the object at the highest point of the trajectory is g

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NOw , at the highest point , as the velocity is only horizontal

velocity at the highest point = v0 * cos(theta)

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let the initial velocity is v0

y = x * tan(theta) - g * x^2/( 2 * (v * cos(theta))^2)

8.8 - 9 = 0.7 * tan(73.1 degree) - 9.8 * 0.7^2/(2 * (v0 * cos(73.1 degree))^2)

solving for v0

v0 = 3.37 m/s

the initial speed of the object is 3.37 m/s