The correct answer would be 1.7 m/s:
Start with what you know. In the y-direction, we know the jumper must fall 15 meters and starts with 0 velocity in the y direction. You can also assume that the acceleration of gravity is pulling down on the jumper at 9.8 m/s. Once you have these three you can plug it into kinematic a equation to find time
x=Vot+1/2at^2
15=(0)t+1/2(9.8)(t)^2
t=1.75
You get time=1.75 seconds. Since this is a kinematics problem, both the x and y direction have the same amount of time. You can then see that the x displacement is 3 to avoid the rocks, and acceleration is 0 in the x direction because no force is speeding it up. Therefore you can use the same equation to find initial velocity and final velocity, which are gonna be the same because we have 0 acceleration:
X=Vot+1/2at^2
3=Vi(1.75)+1/2(0)(1.75)^
Vi=1.7
1.7 is your answer
I have my work in the picture I really like to make charts to help keep everything organized if that helps you
After the ball leaves the thrower's hand, the only force on it is
due to gravity. There's no horizontal force acting on it at all. (C)
Because one pole of the Earth's axis of rotation (the North one) points
almost exactly toward Polaris.
If Polaris had a pimple or a bump somewhere on its edge, you'd see
the bump rotate around the whole edge, like a clock, once a day. But
the whole star appears to stay in one place, because our axis points to it.
We know that speed equals distance between time. Therefore to find the distance we have that d = V * t. Substituting the values d = (72 Km / h) * (1h / 3600s) * (4.0 s) = 0.08Km.Therefore during this inattentive period traveled a distance of 0.08Km
To determine the energy equivalent of an object, we use the famous equation of Einstein which is E=mc^2 where m is the mass of the object and c is the speed of light (3x10^8 m/s). We calculate as follows:
E = mc^2
E = 1.83 kg (3x10^8 m/s)^2
E = 1.647x10^17 J
