A basketball is projected at an angle of 30 degrees. If we want the ball to go into a basket 5 meters away and +2.5 meters upwards vertically, at what speed should we shoot the ball?

Question

anonymous · Answer

in the x or y V0x or V0y or V V means velocity

anonymous · Answer

Its asking for the velocity with the 30 degree angle... so like like vx + vy, polar form?

agent0smith · Answer

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Use $$\Large \Delta y = v_y t + 0.5 a t^2$$where delta y is your change in height, vy is your vsin30.
$$\Large \Delta x = v_x t$$ where vx is your vcos30. You will have to solve simultaneous equations (the t in each equation is equal)

agent0smith · Answer

Delta x is your horizontal displacement.

anonymous · Answer

Can someone actually right it all out and answer this...

agent0smith · Answer

You can at least make an attempt from what i gave. First equation is (-9.8 since gravity acts down making it negative)$$\Large 2.5 = vt \sin 30  + 0.5 (-9.8) t^2$$
second equation$$\Large  5 = v t \cos 30 $$

anonymous · Answer

Thanks... I've attempted for 3 days already, still don't know how to get rid of t

anonymous · Answer

Unless I substitute one of them into the other

agent0smith · Answer

Yes, do that. Use the second equation - solve for t. Plug into the first.

anonymous · Answer

Ok, thanks... i'll try that out later... for the future, if i need to find the velocity (initial) from a projectile question i just substitute right?

agent0smith · Answer

For this type of problem, yes.